<PAGE>   1
                                                                   EXHIBIT 10.31

                        AMENDMENT TO LEASE - CONTRACTION

THIS AMENDMENT is executed at San Diego County, San Diego, Ca 92121 by and
between WebsideStory, Inc., A California Corporation, ("Lessee") and PS Business
Parks, Inc. as Manager and Agent for Owner ("Lessor") for the premises located
at 6450 Lusk Blvd., Suite E103/104/201/203/204/207/208/209, San Diego, CA 92121.
Lessor and Lessee being parties to that certain Lease dated November 4, 1998,
hereby express their mutual desire and intent to decrease the area of the leased
premised by 12,667 rentable square feet effective February 14, 2000 and amend by
this writing those terms, covenants and conditions as hereinafter provided.

AMENDMENTS

"1.01 PREMISES" shall hereafter additionally provide as follows: The square
      footage of the leased premises was 15,854 rentable square feet. The
      square footage of the leased premises shall hereafter be 3,187 rentable
      square feet, and is located and described in the attached Exhibit "A" -
      CONTRACTION and Exhibit "A-1" CONTRACTION. The address of the leased
      Premises shall hereafter be 6450 Lusk Blvd., Suite E103/104, San Diego,
      CA 92121.

"1.07 BASE MONTHLY RENT" shall hereafter additionally provide as follows: The
      Base Monthly Rent was $14,680.00 per month. The Base Monthly Rent shall
      hereafter be $2,932.00 per month in lawful money of the United States of
      America.

      ADJUSTMENTS TO BASE MONTHLY RENT:
      December 1, 2000 through October 31, 2001 shall be $3,091.00 per month.

      SATELLITE DISH:  $200.00 per month
      GENERATOR:       $200.00 per month

      LESSEE'S PROPORTIONATE SHARE OF OPERATING COSTS AND PROPERTY TAXES shall
      hereafter be seven hundred one dollars and fourteen cents $701.14 per
      month and may be adjusted annually.

"1.08 SECURITY DEPOSIT: shall hereafter additionally provide as follows: The
      Security Deposit was $5019.80 and shall hereafter be $3,792.00.

      *$1,200 to be deducted from Security Deposit for the surrender of suites
       E201/202/203/204/207/208/209 (Documentation Fee)

      *1,227.80 to be deducted from Security Deposit to be paid toward Broker
       Commission due.

"1.10 PROPORTIONATE SHARE" shall hereafter additionally provide as follows:
      Lessee's Proportionate share was .1346. Lessee's Proportionate Share
      shall hereafter be .0251.

*LESSEE IS RESPONSIBLE FOR THE RETURN OF MAIL BOX KEYS, FITNESS CENTER CARDS,
DAMAGED CEILING TILES, PLUMBING PROBLEMS AND LIGHTS PER THE SURRENDER AGREEMENT
AND THE CONTRACTION OF SUITES E201/202/203/204/207/208&209. SHOULD THESE ITEMS
NOT BE RETURNED/COMPLETED, LESSEE WILL PAY TO LESSOR THE COST OF SUCH ITEMS.

LESSOR:                                   LESSEE:
PS Business Parks, Inc.                   WebsideStory, Inc.
A California Corporation                  A California Corporation

By its agent
PS Business Parks, L.P.
By: PS Business Parks, Inc.
    General Partner


/s/ PATRICIA ABBOTT                       /s/ MICHAEL CHRISTIAN
-------------------------------------     -------------------------------------
(Authorized Signature)                    (Authorized Signature)

Patricia Abbott, Assistant VP             Michael Christian
-------------------------------------     -------------------------------------
(Title)                                   (Title) Senior V.P.

3/7/00                                    Feb. 16, 2000
-------------------------------------     -------------------------------------
(Date of Execution)                       (Date of Execution)

<PAGE>   2
                           STANDARD INDUSTRIAL LEASE

Lease Preparation Date:  November 4, 1998

Lessor:                  PS Business Parks, Inc., A California Corporation

Lessee:                  WebSideStory, Inc.

Trade Name:              same

1.   Lease Terms

     1.01 Premises: The Premises referred to in this Lease contain
approximately 9,900 rentable square feet and are located on Exhibit "A" as
described in Exhibit "A1" attached. The address of the leases Premises is
               6450 Lusk Blvd.,
               Suites E103, 104, 203, 204, 207, 208
               San Diego, CA 92121.

     1.02 Project: The Project consists of approximately 117,813
rentable/useable square feet.

     1.03 Lessee's Notice Address: Lessee's Notice Address is the address of
the leased Premises as defined in paragraph 1.01 unless otherwise specified
here: same as above.

     1.04 Lessor's Notice Address: Lessor's Notice Address is:
               6750 Lusk Blvd.
               Suite F211
               San Diego, CA 92121.

     1.05 Lessee's Permitted Use: General and Administrative offices for a
computer translation and internet services organization.

     1.06 Lease Term: The Lease Term commences on December 1, 1998 and ends on
October 31, 2001 (35 months, and ____ days).

     1.07 Base Monthly Rent: $7,662.00 in lawful money of the United States of
America.

     1.08 Security Deposit: $*9,990.00 in lawful money of the United States of
America.
         *Currently held by Lessor -- $4,916.20

     1.09 Lease Documentation Fee: $ waived in lawful money of the United
States of America.

     1.10 Proportionate Share: Lessee's Proportionate Share is .0848.

     1.12 Lessee is entitled to 40 vehicle parking spaces subject to the
provisions of section 10 of this Lease.

2.   Demise and Possession

     2.01 Lessor leases to Lessee and Lessee leases from Lessor the Premises
described in subsection 1.01. By entering the Premises, Lessee acknowledges
that it has examined the Premises and accepts the Premises in their present
condition subject to any additional work Lessor has agreed to do as stated on
Exhibit B.

     2.02 If for any reason Lessor cannot deliver possession of the Premises on
the date the Lease commences, Lessor shall not be subject to any liability nor
shall the validity of this Lease be affected. If Lessee has not caused such
delay there shall be a proportionate reduction of the Base Monthly Rent
covering the period between the commencement of the Lease Term and the date
when Lessor can deliver possession. However, either Lessor or Lessee, unless it
is the cause of the delay, has the right to cancel this Lease by written
notification if possession of the Premises is not delivered within ninety (90)
days of the date the Lease Term commences.

*LESSEE MAY OCCUPY SUITE E103 ON NOVEMBER 16, 1998 AND PAY A PRORATED AMOUNT OF
$734.25 for the period of November 16, 1998 through November 30, 1998
<PAGE>   3
3.   BASE MONTHLY RENT

     3.01  Base Monthly Rent: On the first day of each calendar month of the
Lease Term, Lessee will pay, without deduction or offset, prior notice or
demand, Base Monthly Rent at the place designated by Lessor. However, the first
month's rent is due and payable upon execution of this Lease. In the event that
the Term of this Lease commences or ends on a day other than the first day of a
calendar month, a prorated amount of Base Monthly Rent shall be due upon
execution and it will be calculated using a thirty (30) day month.

     A.    At the same time the Base Monthly Rent is adjusted, the Security
Deposit will also be adjusted to equal the new Base Monthly rent amount and the
deficiency is due concurrently with the next payment of Base Monthly Rent.

     3.03  Any installment of rent or any other charge payable which is not
paid within five (5) days after it becomes due will be considered past due and
Lessee will pay to Lessor as Additional Rent a late charge equal to ten percent
(10%) of such installment or the sum of twenty-five dollars ($25.00), whichever
is greater, for each month or fractional month transpiring from the date due
until paid. A twenty-five dollar ($25.00) handling charge will be paid by
Lessee to Lessor for each returned check and, thereafter, Lessee will pay all
future payments of rent or other charges due by money order or cashier's check.

4.   COMMON AREAS

     4.01  Definitions:

     "ENTIRE PREMISES": The Premises, the Project (of which the Premises are a
part), the Common Areas, the land upon which the Project and the Common Areas
are located, along with all other improvements and facilities thereon are
collectively referred to as the "Entire Premises".

     "COMMON AREAS": "Common Area" is defined as all areas and facilities
outside the Premises and within the exterior boundary line of the Entire
Premises that are provided and designated by Lessor for the non-exclusive use of
Lessor, Lessee and other lessees of the Project and their respective employees,
agents, customers and invitees. Common Areas include, but are not limited to:
all parking areas, loading and unloading areas, trash areas, roadways,
sidewalks, walkways, parkways, driveways, corridors, landscaped areas and any
restrooms used in common by lessees.

     4.02  Lessee, its employees, agents, customers and invitees have the
non-exclusive right (in common with other lessees, Lessor, and any other person
granted use by Lessor) to use of the Common Areas. Lessee agrees to abide by and
conform to, and to cause its employees, agents, customers and invitees to abide
by and conform to all rules and regulations established by Lessor subject to
provisions of section 26 and the Rules and Regulations attached to this Lease.


                                    -- 2 --


<PAGE>   4
     4.03 Lessor has the right, in its sole discretion, from time to time, to:
1) make changes to the Common Areas, including without limitation, changes in
the location, size, shape and number of driveways, entrances, parking spaces,
parking areas, ingress, egress, direction of driveways, entrances, corridors,
parking areas and walkways; 2) close temporarily any of the Common Areas for
maintenance purposes so long as reasonable access to the Premises remains
available; 3) add additional buildings and improvements to the Common Areas; 4)
use the Common Areas while engaged in making additional improvements, repairs or
alterations to the Entire Premises or any portion thereof; do and perform any
other acts or make any other changes in, to or with respect to the Common Areas
and Entire Premises as Lessor may, in the exercise of sound business judgment,
deem to be appropriate.

5.   Additional Rent

     5.01 All charges payable by Lessee other than Base Monthly Rent are called
"Additional Rent". Unless this lease provides otherwise, Additional Rent is to
be paid with the next monthly installment of Base Monthly Rent and is subject to
the provisions of 3.03. The term "rent" whenever used in this Lease means Base
Monthly Rent and Additional Rent.

     5.02 Operating Costs

     A.   "Operating Costs" are all costs and expenses of ownership, operation,
maintenance, repair and insurance incurred by Lessor including, but not limited
to, the following: all supplies, materials, labor and equipment, used in or
related to the operation and maintenance of the Common Areas; all utilities,
including but not limited to, water, electricity, gas, heating, lighting, sewer,
waste disposal related to the maintenance or operation of the Common Areas; all
air-conditioning and ventilating costs related to the maintenance or operation
of the Entire Premises; all Lessor's costs in managing, maintaining, repairing,
operating and insuring the Entire Premises, including, for example, clerical,
supervisory, and janitorial staff; all maintenance, management and service
agreements, including but not limited to, janitorial, security, trash removal
related to the maintenance or operation of the Entire Premises; all legal and
accounting costs and fees for licenses and permits related to the ownership and
operation of the Entire Premises; all insurance premiums and costs of fire,
casualty, and liability coverage, rent abatement and earthquake insurance and
any other type of insurance related to the Entire Project; all operation,
maintenance and repair costs to the Common Areas, including but not limited to,
sidewalks, walkways, parkways, parking areas, loading and unloading areas, trash
areas, roadways, driveways, corridors, and landscaped area, including for
example, costs of resurfacing and restriping parking areas; all maintenance and
repair costs of building exteriors (including painting), restrooms used in
common by lessees and signs and directories of the Entire Premises; amortization
(along with reasonable financing charges) of capital improvements made to the
Common Areas which may be required by any government authority or which will
improve the operating efficiency of the Entire Premises; a five percent (5%) fee
for Lessor's supervision of the Common Areas (five percent (5%) of the total
above mentioned costs and expenses incurred in a calendar year). Operating Costs
will not include depreciation of the Entire Premises.

     B.   Lessee shall pay to Lessor Lessee's Proportionate Share of the
Operating Costs as indicated in subsection 1.10. Such payment shall be paid by
Lessee with and in addition to the monthly payment of Base Monthly Rent. Lessee
shall, if Lessor so elects, pay to Lessor on a monthly basis, in advance, the
amount which Lessor reasonably estimates to be Lessee's Proportionate Share of
the Operating Costs. In the event of such election by Lessor, Lessor shall
periodically determine Lessee's share of the actual Operating Costs, and in the
event that the amount which Lessee has paid to Lessor on account of the
estimated Operating Costs is less than his share of such actual Operating costs,
Lessee shall pay such difference to Lessor on the next rent payment date. In the
event that Lessee has paid to Lessor more than his share of such actual
Operating Costs, the amount of such difference shall be credited against
Lessee's payments of Operating Costs next due.

     C.   Failure by Lessor to provide Lessee with a statement by April 1st of
each year shall not constitute a waiver by Lessor of its right to collect
Lessee's share of Operating Costs. In addition, if for any reason Lessor should
not elect to bill Lessee for lump sum Operating Costs or estimates for a
particular calendar year, Lessor's right to charge Lessee for such expenses in
subsequent years is not waived.

     5.03 Taxes

     A.   "Real Property Taxes" are: (i) any fee, license fee, license tax,
business license fee, commercial rental tax, levy, charge, assessment, penalty
or tax imposed by any taxing authority against the Property; (ii) any tax or fee
on Lessor's right to receive, or the receipt of, rent or income from the
Property or against Landlord's business of leasing the Property, (iii) any tax
or charge for fire protection, streets, sidewalks, road maintenance, refuse or
other services provided to the Property by any governmental agency; (iv) any tax
imposed upon this transaction, or based upon a re-assessment of the Project due
to a change in ownership or transfer of all or part of Lessor's interest in the
Property; and (v) any charge or fee replacing, substituting for, or in addition
to any tax previously included within the definition of real property tax. Real
Property Taxes do not, however, include Lessor's federal or state income,
franchise, inheritance or estate taxes.



                                      -3-
<PAGE>   5
      B. Lessee shall pay to Lessor Lessee's Proportionate Share of the Real
Property Taxes as indicated in subsection 1.10. Such payment shall be paid by
Lessee with and in addition to the monthly payment of Base Monthly Rent. Lessee
shall, if Lessor so elects, pay to Lessor on a monthly basis, in advance, the
amount which Lessor reasonably estimates to be Lessee's Proportionate Share of
the Real Property Taxes. In the event of such election by Lessor, Lessor shall
periodically determine Lessee's share of the actual Real Property Taxes, and in
the event that the amount which Lessee has paid to Lessor on account of the Real
Property Taxes is less than his share of such actual Real Property Taxes, Lessee
shall pay such difference to Lessor on the next rent payment date. In the event
that Lessee has paid to Lessor more than his share of such actual Real Property
Taxes, the amount of such difference shall be credited against Lessee's payment
of Real Property Taxes next due.

      C. Personal Property Taxes: Lessee will pay all taxes charged against
trade fixtures, furnishings, equipment or any other personal property belonging
to Lessee. Lessee will have personal property taxes billed separately from the
Project. If any of Lessee's personal property is taxed with the Project, Lessee
will pay Lessor the taxes for the personal property upon demand by Lessor.

      5.04 Based on Lessee's Proportionate Share defined in subsection 1.10,
Lessee agrees to pay as Additional Rent to Lessor its share of any parking
charges, utility surcharges, occupancy taxes, or any other costs resulting from
the statutes or regulations, or interpretations thereof, enacted by any
governmental authority in connection with the use or occupancy of the Project or
the parking facilities serving the Project, or any part thereof.

6.    Security Deposit

      6.01 If Lessee defaults with respect to any provision of this Lease,
Lessor may retain, use or apply all or any part of the Security Deposit to
compensate Lessor for any loss or damage suffered by Lessee's default including
but not limited to, the payment of Base Monthly Rent, Additional Rent or other
rental sums due, and for payment of amounts Lessor is obligated to spend by
reason of Lessee's default. If any portion is so retained, used or applied,
Lessee, upon demand, will deposit with Lessor an amount sufficient to restore
the deposit to its original amount, as adjusted per subsection 3.02. Lessor will
not be required to keep the Security Deposit separate from its general funds,
and Lessee will not be entitled to interest on it. If Lessee fully and
faithfully performs every provision of this Lease, the Security Deposit or a
balance thereof will be returned to Lessee within the time frame permitted by
law. In no event will Lessee have the right to apply any part of the Security
Deposit to any rents payable under this Lease.

7.    Lease Documentation Fee

8.    Use of Premises; Quiet Conduct

      8.01 The Premises may be used and occupied only for Lessee's Permitted Use
as shown in subsection 1.05 and for no other purpose, without obtaining Lessor's
prior written consent. Lessee will comply with all covenants, conditions and
restrictions affecting the Premises. Lessee will promptly comply with all laws,
ordinances, orders and regulations affecting the Premises. Lessee will not
perform any act or carry on any practices that may injure the Project or the
Premises or be a nuisance or menace, or disturb the quiet enjoyment of other
lessees, in the Project including but not limited to equipment which causes
vibration, use or storage of chemicals, heat or noise which is not properly
insulated, or anything which causes noxious or unpleasant odors. Lessee will not
cause, maintain or permit any outside storage on or about the Premises. In
addition, Lessee will not allow any condition or thing to remain on or about the
Premises which diminishes the appearance or aesthetic qualities of the Premises
and/or the Project or the surrounding property. The keeping of a dog or other
animal on or about the Premises is expressly prohibited.

9.    Tenant Improvements

      9.01 Tenant Improvements to be performed in the Premises, if any, will be
performed in accordance with the terms and provisions entitled "Lessor's Work"
contained in "Exhibit B" attached. Thereafter during the Lease Term, Lessor will
be under no obligation to alter, change, decorate or improve the Premises.

10.   Parking

      10.01 Lessee and Lessee's customers, suppliers, employees, and invitees
have the non-exclusive right to park in common with other lessees in the parking
facilities as designated by Lessor. Lessee agrees not to overburden the parking
facilities and agrees to cooperate with Lessor and other lessees in the use of
the parking facilities. Lessor reserves the right to, on an equitable basis,
assign specific spaces with or without charge to Lessee as Additional Rent, make
changes in the parking layout from time to time, and to establish reasonable
time limits on parking.

                                      -4-
<PAGE>   6
11.   Utilities

      11.01 Lessee will pay for all gas, heat, light, power, electricity, or
other services metered, chargeable to or provided to the Premises. Lessor
reserves the right to install separate meters for any such utility.

      11.02 Lessor will not be liable or deemed in default to Lessee nor will
there be any abatement of rent or any interruption or reduction of utilities or
services not caused by any act of Lessor or any act reasonably beyond Lessor's
control. Lessee agrees to comply with energy conservation programs implemented
by Lessor by reason of enacted laws or ordinances.

      11.03 Lessee will contract and pay for all telephone and such other
services for the Premises subject to the provisions of subsection 12.03.

12.   Alterations, Mechanic's Liens

      12.01 Lessee will not make any alterations to the interior of the
Premises, without Lessor's prior written consent which will not be unreasonably
withheld. If Lessor gives its consent, no such alterations will proceed without
Lessor's prior written approval of (i) Lessee's contractor, (ii) certificates of
insurance by Lessee's contractor for public liability and automobile liability
and property damage insurance with limits not less than
$1,000,000/$250,000/$500,000 respectively endorsed to show Lessor as an
additional insured and for worker's compensation as required and (iii) detailed
plans and specification for such work. In addition, before alterations may
begin, valid building permits or other permits or licenses required must be
furnished to Lessor, and, once the alterations begin, Lessee will diligently and
continuously pursue their completion. At Lessor's option, any alterations may
become part of the realty and belong to Lessor. If requested by Lessor, Lessee
will pay, prior to the commencement of construction, an amount determined by
Lessor necessary to cover the costs of demolishing such alterations and/or the
cost of returning the Premises to its condition prior to such alterations. As a
further condition to giving such consent, Lessor may require Lessee to provide
Lessor, at Lessee's sole cost and expense, a payment and performance bond in
form acceptable to Lessor, in a principal amount not less than one and one-half
times the estimated costs of such alterations, to ensure Lessor against any
liability for mechanic's and materialmen's liens and to ensure completion of
work and such bond will continue in force for a period no less than 131 days
after the completion of such work.

      12.02 Notwithstanding anything in subsection 12.01, Lessee may, with
written consent of Lessor, install trade fixtures, equipment, and machinery in
conformance with the ordinances of the applicable city and county, and they may
be removed upon termination of this Lease provided the Premises are not damaged
by their removal.

      12.03 All private telephone systems and/or other related
telecommunications equipment and lines may not be installed without Lessor's
prior written consent. In addition, if Lessor gives consent all equipment must
be installed within Lessee's Premises and, upon termination of this Lease
removed and the Premises restored to the same condition as before such
installation.

      12.04 Lessee will pay all costs for alterations and will keep the
Premises, the Project and the underlying property free from any liens arising
out of work performed for, materials furnished to, or obligation incurred by
Lessee as outlined in the applicable parts of subsection 12.01 above.

      12.05 Lessor will have the right to construct or permit construction of
tenant improvements in or about the Project for existing and new lessees and to
alter any public areas in and around the Project. Notwithstanding anything which
may be contained in this Lease, Lessee understands this right of Lessor and
agrees that such construction will not be deemed to constitute a breach of this
Lease by Lessor and Lessee waives any such claim which it might have arising
from such construction.

13.   Fire Insurance; Hazards and Liability Insurance

      13.01 Except as expressly provided as Lessee's Permitted Use, subsection
1.05, or as otherwise consented to by Lessor in writing, Lessee shall not do or
permit anything to be done within or about the Premises which will increase the
existing rate of insurance on the Project or shall, at its sole cost and
expense, comply with any requirements pertaining to the Premises or any
insurance organization insuring the Project and Project-related apparatus.
Lessee agrees to pay to Lessor, as Additional Rent, any increases in premiums on
policies resulting from Lessee's Permitted Use or other use consented to by
Lessor which increases Lessor's premiums or requires extended coverage by Lessor
to insure the Premises.

      13.02 Lessee, at all times during the term of this Lease and at Lessee's
sole expense, will maintain a policy of standard fire and extended coverage
insurance with "all risk" coverage on all Lessee's improvements and alterations
in or about the Premises and on all personal property and equipment to the
extent of at least ninety percent (90%) of their full replacement value. The
proceeds from this policy will be used by Lessee for the replacement of personal
property and equipment and the restoration of Lessee's improvements and/or
alterations. This policy will contain an express waiver, in favor of Lessor, of
any right of subrogation by the insurer.

                                      -5-
<PAGE>   7
     13.03 Lessee, at all times during the term of this Lease and at Lessee's
sole expense, will maintain a policy of comprehensive general liability
coverage with limits of not less than $1,000,000 combined single loss for
bodily injury and property damage insuring against all liability of Lessee and
its authorized representatives arising out of or in connection with Lessee's
use or occupancy of the Premises. This policy of insurance will name Lessor as
an additional insured and will include an express waiver of subrogation by the
insurer in favor of Lessor and will release Lessor from claims for damage to
any person, to the Premises, and to the Project, and to Lessee's personal
property, equipment, improvements and alterations in or on the Premises of the
Project, caused by or resulting from risks which are to be insured against by
Lessee under this Lease.

     13.04 All insurance required to be provided by Lessee under this Lease
will (a) be issued by an insurance company authorized to do business in the
state in which the Premises are located and which is satisfactory to Lessor,
(b) be primary and noncontributing with any insurance carried by Lessor, and
(c) contain an endorsement requiring at least thirty (30) days prior written
notice of cancellation to Lessor before cancellation or change in coverage,
scope or limit of any policy. Lessee will deliver a certificate of insurance or
a copy of the policy to Lessor within thirty (30) days of execution of the
Lease and will provide evidence of renewed insurance coverage at each
anniversary, prior to the expiration of any current policies. Lessee's failure
to provide evidence of this coverage to Lessor may, in Lessor's sole
discretion, constitute a default under this Lease.

14.  Indemnification and Waiver of Claim

     14.01 Lessee waives all claims against Lessor for damage to any property
in or about the Premises and for injury to any persons, including death
resulting therefrom, regardless of cause or time of occurrence. Lessee will
defend, indemnify and hold Lessor harmless from and against any and all claims,
actions, proceedings, expenses, damages and liabilities, including attorneys'
fees, arising out of, connected with, or resulting from any use of the Premises
by Lessee, its employees, agents, visitors or licensees, except for any damage
or injury which is the direct result of intentional acts by Lessor, its
employees, agents, visitors or licensees.

15.  Repairs

     15.01 Lessee shall, at its sole expense, keep and maintain the Premises and
every part thereof (excepting air-conditioning, common use equipment, exterior
walls and roofs, which Lessor agrees to repair unless damages are due to the
neglect or intentional acts of Lessee or its agents, employees, visitors or
licensees), including interior windows, skylights, doors, any store fronts and
the interior of the Premises, in good and sanitary order, condition and repair.
Lessee will, also, at its sole cost keep and maintain all utilities, fixtures,
plumbing and mechanical equipment used by Lessee in good order and repair and
furnish all expendables (light bulbs [unless provided by Lessor], paper goods,
soaps, etc.) used in the Premises. The standard for comparison and need of
repair will be the condition of the Premises at the time of commencement of
this Lease and all repairs will be made by a licensed and bonded contractor
approved by Lessor.

     15.02 Lessee will not make repairs to the Premises at the cost of Lessor,
whether by deduction of rent or otherwise or vacate the Premises or terminate
the Lease with abatement or termination of rent because repairs are not made.
If during the Term, any alteration, addition or change to the Premises is
required by legal authorities, Lessee, at its sole expense, shall promptly make
the same. Lessor reserves the right to make any such repairs not repaired or
maintained in good condition by Lessee and Lessee shall reimburse Lessor for
all such costs upon demand. If such repairs have not been made within 30 days
of notice to repair by Lessor to Lessee, Lessor may make such repairs and such
costs of repairs shall be at Lessee's expense. Failure to pay such expenses
within 30 days of presentation, shall be deemed a breach of this Lease.

16.  Auction, Signs, Landscaping

     16.01 Lessee will not conduct or permit to be conducted any sale by
auction on the Premises. Lessor will have the right to control landscaping and
approve the placement, size, and quality of signs. Lessee shall comply with the
terms and conditions regarding sign criteria set forth in Exhibit "C" attached.
Lessee will not make alterations or additions to the landscaping and will not
place signs which are visible from the outside of any buildings of the Project
without prior written consent of Lessor. Lessor will have the right in its sole
discretion to withhold its consent. Any signs not in conformity with this Lease
may be removed by Lessor at Lessee's expense.



                                      -6-
<PAGE>   8
17.     Entry By Lessor

     17.01 Lessee will permit Lessor and Lessor's agents to enter the Premises
at all reasonable times for the purpose of inspecting the same, or for the
purpose of maintaining the Project, or for the purpose of making repairs,
alternations or additions to any portion of the Project, including the erection
and maintenance of such scaffolding, canopies, fences and props as may be
required, or for the purpose of posting notices of nonresponsibility for
alterations, addition or repairs, or for the purpose of showing the Premises to
prospective tenants during the last six months of the lease Term, or placing
upon the Project any usual or ordinary "for sale" signs, without any rebate of
rents and without any liability to Lessee for any loss of occupation or quiet
enjoyment of the Premises thereby occasioned. Lessee will permit Lessor at any
time within sixty (60) days prior to the expiration of this Lease, to place upon
the Premises any usual or ordinary "to let" or "to lease" signs. For each of the
above purposes, Lessor will at all times have and retain a key with which to
unlock all of the doors in, upon and about the Premises, excluding Lessee's
vaults and safes. Lessee will not alter any lock or install a new or additional
lock or any bolt on any door of the Premises without the prior written consent
of Lessor, which will not be unreasonably withheld. If Lessor gives its consent,
Lessee will furnish Lessor with a key and Lessor retains the right to charge
Lessee for restoring any altered doors to their condition prior to the
installation of the new or additional locks.

18.     Abandonment

     18.01  Lessee will not vacate or abandon the Premises at any time during
the Lease Term or permit the Premises to remain unoccupied for a period longer
than fifteen (15) consecutive days during the Lease Term. If Lessee abandons,
vacates or surrenders the Premises, or is dispossessed by process of law, or
otherwise, any personal property belonging to Lessee left in or about the
Premises will, at the option of Lessor be deemed abandoned and may be disposed
of by Lessor in the manner provided for by the laws of the state in which the
Premises are located.

19.     Destruction

     19.01  Should the Premises or the building on the Premises be partially
destroyed by any cause not the fault of Lessee (or any person in or about the
Premises with the consent, expressed or implied, of Lessee), this Lease will
continue in full force and effect and Lessor, at Lessor's own cost and expense,
will promptly commence the work of repairing and restoring the Premises to their
prior condition providing the then work can be accomplished under all applicable
government laws and regulations within sixty (60) working days from the date of
damage at a cost not exceeding twenty-five percent (25%) of the total
replacement cost of the Premises. Within thirty (30) days of the occurrence of
partial destruction, Lessor may terminate this Lease as of the date of the
occurrence if nine (9) months or less remain in the Lease Term.

     19.02    Should the Premises or the building in which the Premises are a
part be so far destroyed by any cause not the fault of Lessee (or any person in
or about the Premises with the consent, expressed or implied, of Lessee) that
they cannot be repaired or stored to their former condition within sixty (60)
days of the date of damage or at a cost exceeding twenty-five percent(25%) of
the total replacement cost of the Premises, Lessor may at Lessor's options
either:

     A. Continue this Lease in full force and effect by repairing and restoring,
at Lessor's own cost and expense, the Premises to their former condition; or

     B. Terminate this Lease by giving Lessee written notice of such
termination.

     19.03 Should the Premises be partially or totally destroyed by any cause of
Lessee, or any person in or about the Premises with the consent, expressed or
implied, of Lessee, this Lease will remain in full force and effect and Lessee
shall immediately commence work to repair the damage and diligently pursue its
completion.

     19.04 Any insurance proceeds received by Lessor because of the total or
partial destruction of the Premises or the building on the Premises will be the
sole property of Lessor, free from any claims of Lessee, and may be used by
Lessee for whatever purpose Lessor may desire.

     19.05 Should Lessor elect to repair and restore the Premises to their
former condition, or should Lessor be required to restore the Premises to their
former condition, there will be a proportional abatement in the amount of rent
payable during the period of repairs and restoration as long as Lessee (or any
person in or about the Premises with the consent, expressed or implied, of
Lessee) is not the cause of the total or partial destruction. The rent due under
the terms of the Lease will be reduced between the date of destruction and the
date of completion of restoration and repairs based on the extent to which
destruction interferes with Lessee's use of the Premises.


                                   -- 7 --
<PAGE>   9
20. Assignment, Subletting and Transfers of Ownership

     20.01 Lessee will not directly or indirectly, voluntarily or by operation
of law, assign, sell, mortgage, encumber, convey, or otherwise Transfer all or
any part of Lessee's Leasehold estate, or permit the Premises to be occupied by
anyone other than the Lessee and Lessee's employees or sublet the Premises or
any portion thereof (collectively called "Transfer") without Lessor's prior
written consent. If Lessee desires at any time to Transfer this Lease, Lessee
shall first give written notice to Lessor of its desire to do so, which notice
shall contain (a) the identity of the proposed Transferee, (b) the terms and
provisions of the proposed Transfer, (c) the nature of the proposed Transferee's
business to be carried on in the Premises, (d) a detailed summary of the
business background and financial condition of the proposed Transferee, and (e)
such financial information as deemed necessary by Lessor to evaluate any
proposed Transfer. All of the foregoing information shall be provided to Lessor
by Lessee at least sixty (60) days in advance of Lessee's proposed Transfer
date.

     20.02 Lessor will not unreasonably withhold its consent to any proposed
Transfer except that such consent need not be granted if: (a) in the reasonable
judgment of Lessor the Transferee is of a character or is engaged in a business
which is not in keeping with the standards of the Lessor for the Project; (b) in
the reasonable judgment of Lessor any purpose for which the Transferee intends
to use the Premises is not in keeping with the standards of Lessor for the
Project; provided in no event may any purpose for which Transferee intends to
use the Premises be in violation of this Lease; (c) the portion of the Premises
subject to the Transfer is not regular in shape with appropriate means of
entering and exiting, including adherence to any local, county or other
governmental codes, or is not otherwise suitable for the normal purposes
associated with such a Transfer; (d) the proposed Transferee be at least as
financially responsible as Lessee was expected to be at the time of the
execution of this Lease or (e) Tenant is in default under this Lease.

     20.03 In the event Lessor consents to a Transfer, Lessee will pay Lessor
the excess, if any, of the rent and other charges reserved in the Transfer over
the allocable portion of the rent and other charges hereunder for that portion
of the Premises subject to the Transfer. For the purpose of this section, the
rent reserved in the Transfer will be deemed to include any lump sum payment or
other consideration given to Lessee in consideration for the Transfer. Lessee
will pay or cause the Transferee to pay to Lessor this additional rent together
with the monthly installments of rent due.

     20.04 Any consent to any Transfer which may be given by Lessor, or the
acceptance of any rent, charges or other consideration by Lessor from Lessee or
any third party, will not constitute a waiver by Lessor of the provisions of
this Lease or a release of Lessee from the full performance by it or the
covenants stated herein; and any consent given by Lessor to any Transfer will
not relieve Lessee (or any transferee of Lessee) from the above requirements for
obtaining the written consent of Lessor to any subsequent Transfer.

     20.05 If a default under this Lease should occur while the Premises or any
part of the Premises are assigned, sublet or otherwise transferred, Lessor, in
addition to any other remedies provided for within this Lease or by law, may at
its option collect directly from the Transferee all rent or other consideration
becoming due to Lessee under the Transfer and apply these monies against any
sums due to Lessor by Lessee; and Lessee authorizes and directs any Transferee
to make payments of rent or other consideration direct to Lessor upon receipt of
notice from Lessor. No direct collection by Lessor from any Transferee should be
construed to constitute a novation or a release of Lessee or any guarantor of
Lessee from the further performance of its obligations in connection with this
Lease.

     20.06 Any Transfer without the Lessor's consent shall be void and shall, at
the option of Lessor, terminate this Lease.

     20.07 If Lessee requests a consent of Lessor to any Transfer, then Lessee
shall, upon demand, pay Lessor an administrative fee of One Hundred Fifty
Dollars ($150.00) plus any attorneys' fees reasonably incurred by Lessor in
connection with such request.

21. Breach By Lessee

     21.01 Lessee will be in breach of this Lease if at any time during the term
of this Lease (and regardless of the pendency of any bankruptcy, organization,
receivership, insolvency or other proceedings in law, in equity or before any
administrative tribunal which have or might have the effect of preventing Lessee
from complying with the terms of this Lease):

     A.  Lessee fails to make payment of any installment of Base Monthly Rent,
Additional Rent, or of any other sum herein specified to be paid by Lessee, and
such failure is not cured within three (3) days after Lessor's written notice
to Lessee of such failure of payment, which notice shall be in lieu of and not
in addition to any notice required by statute; or

     B.  Lessee fails to observe or perform any of its other covenants,
agreements or obligations hereunder, and such failure is not cured within ten
(10) days after Lessor's written notice to Lessee of such failure, which notice
shall be in lieu of and not in addition to any notice required by statute
provided, however, that if the nature of Lessee's obligation is such that more
than ten (10) days are required for performance, then Lessee will not be in
breach if Lessee commences performance within such ten (10) day period and
thereafter diligently prosecutes the same to completion; or




<PAGE>   10
     C. Lessee becomes insolvent, makes a transfer in fraud of its creditors,
makes a transfer for the benefit of its creditors, voluntarily files for
bankruptcy, is adjudged bankrupt or insolvent in proceedings filed against
Lessee, a receiver, trustee, or custodian is appointed for all or substantially
all of Lessee's assets, fails to pay its debts as they become due, convenes a
meeting of all or a portion of its creditors, or performs any acts of bankruptcy
or insolvency, including the selling of its assets to pay creditors, or
indicates a general inability to pay its obligations hereunder; or

     D. Lessee has abandoned the Premises as defined in section 18 above.

22. Remedies of Lessor

     22.01 Termination of Lease After Breach: If lessee breaches this Lease and
abandons the Premises before the end of the term, or if its right to possession
is terminated by Lessor because of Lessee's breach of this Lease, then this
Lease may be terminated by Lessor at its option. On such termination Lessor may
recover from Lessee, in addition to the remedies permitted by law:

     A. The worth at the time of award of the unpaid rents which had been earned
at the time of termination;

     B. The worth at the time of award of the amount by which the unpaid rents
which would have been earned after termination until the time of award exceeds
the amount of such rental loss that Lessee proves could have been reasonably
avoided;

     C. The worth at the time of award of the amount by which the unpaid rents
for the balance of the Lease Term after the time of award exceeds the amount of
such rental loss for such period that Lessee proves could be reasonably avoided;
and

     D. Any other amount necessary to compensate Lessor for all the damage
proximately caused by Lessee's breach of its obligations under this Lease, or
which in the ordinary course of events would be likely to result therefrom. The
damage proximately caused by Lessee's breach will include, without limitation,
(i) expenses for cleaning, repairing or restoring the Premises, (ii) expenses
for altering, remodeling or otherwise improving the Premises for the purpose of
reletting, (iii) brokers' fees and commissions, advertising costs and other
expenses of reletting the Premises, (iv) costs of carrying the Premises such as
taxes, insurance premiums, utilities and security precautions, (v) expenses in
retaking possession of the Premises, (vi) attorneys' fees and court costs, (vii)
any unearned brokerage commissions paid in connection with this Lease and (viii)
reimbursement of any previously waived Base Rent or Additional Rent.

     22.02 Continuation of Lease After Breach: Notwithstanding the foregoing, in
the event Lessee has breached this Lease and abandoned the Premises, this Lease,
at Lessor's option, will continue in full force and effect so long as Lessor
does not terminate Lessees' right to possession of the Premises, and in such
event Lessor may enforce all of its rights and remedies under this Lease,
including the right to recover rent as it becomes due. For purposes of this
subsection 22.03, the following acts by Lessor will not constitute the
termination of Lessee's right to possession of the premises:

     A. Acts of maintenance or preservation or efforts to relet the Premises,
including, but not limited to, alterations, remodeling, redecorating, repairs,
replacements and/or painting as Lessor shall consider advisable for the purpose
of reletting the Premises or any part thereof; or

     B. The appointment of a receiver upon the initiative of Lessor to protect
Lessor's interest under this Lease or in the Premises.

     22.03 In the event of bankruptcy, Lessee assigns to Lessor all its rights,
title and interest in the Premises as security for its obligations and covenants
set forth in this Lease.

     22.04 Definitions and Incidental Rights

     A. The "worth at the time of award" of the amounts referred to in
subsection 22.01A, and subsection 22.01B, will be computed by allowing interest
at the rate of ten percent (10%) per annum. The "worth at the time of award" of
the amount referred to above in subsection 22.01C will be computed by
discounting the amount at the discount rate of the Federal Reserve Bank of San
Francisco in effect at the time of award, plus one percent (1%).

     B. Any efforts by Lessor to lessen the damages caused by Lessee's breach of
this Lease will not waive Lessor's right to recover the damages set forth above.

     C. Nothing herein will be construed to affect other provisions of this
Lease regarding Lessor's right to indemnification from Lessee for liability
arising prior to the termination of this Lease for personal injuries or property
damage.


                                      -9-
<PAGE>   11
     D.   No right or remedy conferred upon or reserved to Lessor in this Lease
is intended to be exclusive of any other right or remedy granted to Lessor by
statute or common law, and each and every such right and remedy will be
cumulative.

23.  Surrender of Lease Not Merger

     23.01     The voluntary or other surrender of this Lease by Lessee, or a
mutual cancellation thereof, will not work a merger and will, at the option of
Lessor, terminate all or any existing transfers, or may, at the option of
Lessor, operate as an assignment to it of any or all of such transfers.

24.  Attorneys Fees / Collection Charges

     24.01     In the event of any legal action or proceeding between the
parties hereto, actual attorneys' fees and expenses of the prevailing party in
any such action or proceeding will be added to the judgment therein. Should
Lessor be named as defendant in any suit brought against Lessee in connection
with or arising out of Lessee's occupancy hereunder, Lessee will pay to Lessor
its costs and expenses incurred in such suit, including actual attorneys' fees.

     24.02     If Lessor utilizes the services of any attorney at law for the
purpose of collecting any rent due and unpaid by Lessee after three (3) days'
written notice to Lessee of such nonpayment of rent or in connection with any
other breach of this Lease by Lessee, Lessee agrees to pay Lessor actual
attorneys' fees as determined by Lessor for such services, regardless of the
fact that no legal action may be commenced or filed by Lessor.

25.  Condemnation

     25.01     If twenty-five percent (25%) or more of the Premises is taken for
any public or quasi-public purpose by any lawful government power or authority,
by exercise of the right of appropriation, reverse condemnation, condemnation or
eminent domain, or sold to prevent such taking, the Lessee or the Lessor may at
its option terminate this Lease as of the effective date thereof. Lessee will
not because of such taking assert any claim against the Lessor or the taking
authority for any compensation because of such taking, and Lessor will be
entitled to receive the entire amount of any award without deduction for any
estate of interest of Lessee. If less than twenty-five percent (25%) of the
Premises is taken, Lessor at its option may terminate this Lease. If Lessor does
not so elect, Lessor will promptly proceed to restore the Premises to
substantially its same condition prior to such partial taking, allowing for any
reasonable effects of such taking, and a proportionate allowance will be made to
Lessee for the rent corresponding to the time during which, and to the part of
the Premises which, Lessee is deprived on account of such taking and
restoration.

26.  Rules and Regulations

     26.01     Lessee will faithfully observe and comply with the Rules and
Regulations printed on or attached to this Lease and Lessor reserves the right
to modify and amend them as it deems necessary. Lessor will not be responsible
to Lessee for the nonperformance by any other lessee or occupant of the Project
of any of said Rules and Regulations.

     26.02     Violation of any such Rules and Regulations shall be deemed a
material breach of the Lease by Lessee.

27.  Estoppel Certificate

     27.01     Lessee will execute and deliver to Lessor, within ten (10) days
of receiving written notice, a statement in writing certifying that this Lease
is unmodified and in full force and effect (or, if modified, stating the nature
of such modification) and the date to which rent and other charges are paid in
advance, if any, and acknowledging that there are not, to Lessee's knowledge,
any uncured defaults on the part of Lessor hereunder or specifying such defaults
if they are claimed. Any such statement may be conclusively relied upon by any
prospective purchaser or encumbrancer of the Premises. Lessee's failure to
deliver such statement within such time shall be conclusive upon Lessee that (1)
this Lease is in full force and effect, without modification except as may be
represented by Lessor; (2) there are no uncured defaults in Lessor's
performance; and (3) not more than one (1) month's rent has been paid in
advance.

28.  Sale By Lessor

     28.01     In the event of a sale or conveyance by Lessor of the Project the
same shall operate to release Lessor from any liability upon any of the
covenants or conditions, expressed or implied, herein contained in favor of
Lessee, and in such event Lessee agrees to look solely to the responsibility of
the successor in interest of Lessor in and to this Lease. This Lease will not be
affected by any such sale, and Lessee agrees to attorn to the purchaser or
assignee.
<PAGE>   12
29.  Notices

     29.01  All notices, statements, demands, requests, consents, approvals,
authorizations, offers, agreements, appointments or designations under this
Lease by either party to the other will be in writing and will be considered
sufficiently given and served upon the other party if sent by certified mail,
return receipt requested, postage prepaid, and addressed as indicated in
subsection 1.03 and subsection 1.04.

30.  Waiver

     30.01  The failure of Lessor to insist in any one or more cases upon the
strict performance of any term, covenant or condition of this Lease will not be
construed as a waiver of a subsequent breach of the same or any other covenant,
term or condition; nor shall any delay or omission by Lessor to seek a remedy
for any breach of this Lease be deemed a waiver by Lessor of its remedies or
rights with respect to such a breach.

31.  Lessee's Intent, Holding over

     31.01  Lessee will give Lessor, ninety (90) days prior to the expiration of
the Lease Term, written notification of Lessee's intent to either remain in or
vacate the Premises on the Lease Expiration Date. If Lessee does not notify
Lessor by the date specified herein, Lessor deems that Lessee will vacate the
Premises by the Lease Expiration Date and Lessor will have no further
obligation.

     31.02  Any holding over after the expiration or termination of the term of
this Lease, or after any notice given by Lessor to Lessee terminating this
Lease, such possession by Lessee will be deemed to be a month-to-month tenancy
terminable on thirty (30) day notice at any time by either party. All provisions
of this Lease, except those pertaining to term and rent, will apply to the
month-to-month tenancy. Lessee will pay Base Monthly Rent in an amount equal to
150% of rent for the last full calendar month during the regular term.

32.  Project Plan

     32.01  In the event Lessor requires the Premises for use in conjunction
with another suite or for other reasons connected with the Project planning
program, Lessor, upon notifying Lessee in writing, shall have the right to move
Lessee to space in the Project of which the Premises forms a part, at Lessor's
sole cost and expense (excluding private telephone systems which Lessee must
bear the cost of moving and installing), and the terms and conditions of the
original Lease will remain in full force and effect excepting that the Premises
will be in a new location. However, if the new space does not meet with Lessee's
approval, Lessee will have the right to cancel this Lease upon giving Lessor
thirty (30) days' notice within ten (10) days of receipt to Lessor's
notification. Should Lessee elect to cancel the Lease as provided in this
paragraph, the effective expiration date will equal the projected move-in date
of the suite Lessor wishes Lessee to move to as indicated in Lessor's written
notification to Lessee.

33.  Default of Lessor / Limitation of Liability

     33.01  In the event of any default by Lessor hereunder, Lessee agrees to
give notice of such default, by registered mail, to Lessor at Lessor's Notice
Address as stated in subsection 1.04 and to offer Lessor a reasonable
opportunity to cure the default.

     33.02  In the event of any actual or alleged failure, breach or default
hereunder by Lessor, Lessee's sole and exclusive remedy will be against Lessor's
interest in the Project, and no partner of Lessor will be sued, be subject to
service of process, or have a judgment obtained against him in connection with
any alleged breach or default, and no writ of execution will be levied against
the assets of any partner of Lessor. The covenants and agreements are
enforceable by Lessor and also by any partner of Lessor.

34.  Release of Partners of Lessor

     34.01  If Lessee has any claim against Lessor under or arising out of this
Lease, Lessee's sole recourse shall be against the assets of Lessor and Lessee
further waives any and all right to assert any claim against, or obtain any
damages from, the partners, employees, officers, directors or agents of Lessor.

35.  Expansion Clause

     35.01  If during the Lease Term, Lessee executes a Lease within the Project
for space larger than the present premises with a Lease term at least equal to
that which remains on this Lease or one (1) year, whichever is greater, with a
Base Monthly Rent amount at least equal to the present Base Monthly Rent of this
Lease, this Lease shall be terminated upon the commencement date of the Lease
for such substitute space. Notwithstanding the above-stated, Lessee shall remain
obligated to pay for any adjustments in rent pursuant to sections 3, 4 and 5 due
Lessor as a result of Lessee's tenancy hereunder and this obligation shall
survive the termination of this Lease pursuant to this section 35.



                                    -- 11 --

<PAGE>   13
36.  Subordination

     36.01  Without the necessity of any additional document being executed by
Lessee for the purpose of effecting a subordination, and at the election of
Lessor or any mortgagee with a lien on the Project or any ground lessor with
respect to the Project, this Lease will be subject and subordinate at all time
to (a) all ground leases or underlying leases which may now exist or hereafter
be executed affecting the Project, and (b) the lien of any mortgage or deed of
trust which may now exist or hereafter be executed in any amount for which the
Project, ground leases or underlying leases, or Lessor's interest or estate in
any of said items is specified as security. In the event that any ground lease
or underlying lease terminates for any reason or any mortgage or deed of trust
is foreclosed or a conveyance in lieu of foreclosure is made for any reason,
Lessee will, notwithstanding any subordination, attorn to and become the Lessee
of the successor in interest to Lessor, at the option of such successor in
interest. Lessee covenants and agrees to execute and deliver, upon demand by
Lessee and in the form requested by Lessor any additional documents evidencing
the priority or subordination of this Lease with respect to any such ground
lease or underlying leases or the lien of any such mortgage or deed of trust.
Lessee hereby irrevocably appoints Lessor as attorney-in-fact of Lessee to
execute, deliver and record any such document in the name and on behalf of
Lessee.

37.  Miscellaneous Provisions

     37.01  Whenever the singular number is used in this Lease and when required
by the context, the same will include the plural, and the masculine gender will
include the feminine and neuter genders, and the word "person" will include
corporation, firm, partnership, or association. If there be more than one
Lessee, the obligations imposed upon Lessee under this Lease will be joint and
several.

     37.02  The headings or titles to paragraphs of this Lease are not a part of
this Lease and will have no effect upon the construction or interpretation of
any part of this Lease.

     37.03  This instrument contains all of the agreements and conditions made
between the parties to this Lease and may not be modified orally or in any other
manner than by an agreement in writing signed by all parties to this Lease.
Lessee acknowledges that neither Lessor nor Lessor's agents have made any
representation or warranty as to the suitability of the Premises to the conduct
of Lessee's business. Any agreements, warranties or representations not
expressly contained herein will in no way bind either Lessor or Lessee, and
Lessor and Lessee expressly waive all claims for damages, by reason of any
statement, representation, warranty, promise or agreement, if any, not contained
in this Lease.

     37.04  Time is of the essence of each term and provision of this Lease.

     37.05  Except as otherwise expressly stated, each payment required to be
made by Lessee is in addition to and not in substitution for other payments to
be made by Lessee.

     37.06  Subject to section 20, the terms and provisions of this Lease are
binding upon and inure to the benefit of the heirs, executors, administrators,
successors and assigns of Lessor and Lessee.

     37.07  All covenants and agreements to be performed by Lessee under any of
the terms of this Lease will be performed by Lessee at Lessee's sole cost and
expense and without any abatement of rent.

     37.08  In consideration of Lessor's covenants and agreements hereunder,
Lessee hereby covenants and agrees not to disclose any terms, covenants or
conditions of this Lease or any other party without the prior written consent of
Lessor.

38.  Deposit Agreement

     38.01  Lessor and Lessee hereby agree that Lessor will be entitled to
immediately endorse and cash Lessee's good faith rent and the Security Deposit
check(s) accompanying this Lease. It is further agreed and understood that such
action will not guarantee acceptance of this Lease by Lessor, but, in the event
Lessor does not accept this Lease, such deposits will be refunded in full to
Lessee. This Lease will be effective only after Lessee has received a copy fully
executed by Lessor.

39.  Governing Law

     39.01  This Lease is governed by and construed in accordance with the laws
of the state in which the Premise are located, and venue of any suit will be in
the county where the Premises are located.

40.  Severability

     40.01  If any provision of this Lease is found to be unenforceable, all
other provisions shall remain in full force and effect.


                                    -- 12 --

<PAGE>   14
41.  Landlord's Lien

     41.01 LESSOR HEREUNDER WILL HAVE THE BENEFIT OF, AND THE RIGHT TO, ANY AND
ALL LANDLORD'S LIENS PROVIDED UNDER THE LAW BY WHICH THIS LEASE IS GOVERNED.

42.  Special Provisions

     42.01 Special provisions of this Lease number 43 through 51 are attached
hereto and made a part hereof. If none; so state in the following space:
_________________________

     IN WITNESS WHEREOF, Lessor and Lessee have executed this Lease as of the
day and year indicated by Lessor's execution date as written below.

     Individuals signing on behalf of a Lessee warrant that they have the
authority to bind their principals. In the event that Lessee is a corporation,
Lessee shall deliver to Lessor, concurrently with the execution and delivery of
this Lease, a certified copy of corporate resolutions adopted by Lessee
authorizing said corporation to enter into and perform the Lease and
authorizing the execution and delivery of the Lease on behalf of the
corporation by the parties executing and delivering this Lease. THIS LEASE,
WHETHER OR NOT EXECUTED BY LESSEE, IS SUBJECT TO ACCEPTANCE BY LESSOR, ACTING
ITSELF OR BY ITS AGENT ACTING THROUGH ITS PRESIDENT AND VICE PRESIDENT AT ITS
HOME OFFICE.


LESSOR                                  LESSEE
     PS Business Parks, Inc.                 WebSideStory, Inc.
     A California Corporation                A California Corporation

_____________________________           _____________________________
     By its agent
     PS Business Parks, L.P.
     By:  PS Business Parks, Inc.
          General Partner


By /s/ PATRICIA ABBOTT                  By /s/ BLAISE BARRELET
   --------------------                    --------------------
   AUTHORIZED SIGNATURE                    AUTHORIZED SIGNATURE

Patricia Abbott, Regional               Blaise Barrelet, President
  Manager
-------------------------               --------------------------
         TITLE                                    TITLE

Date 12/7/98                            Date
     --------------------                    ---------------------
     EXECUTION DATE

By ______________________               By _______________________
     AUTHORIZED SIGNATURE                    AUTHORIZED SIGNATURE

_________________________               __________________________
        TITLE                                     TITLE

Date ____________________               Date _____________________
       EXECUTION DATE


                                     - 13 -
<PAGE>   15
43.  HAZARDOUS MATERIALS

     43.01     Compliance with Law.

     Lessee, at Lessee's expense, shall comply with all laws, rules, orders,
ordinances, directions, regulations and requirements of federal, state, county
and municipal authorities pertaining to Lessee's use of the Premises and with
the recorded covenants, conditions and restrictions, regardless of when they
become effective, including, without limitation, all applicable federal, state,
and local laws, regulations or ordinances pertaining to air and water quality,
Hazardous Materials (as hereinafter defined), waste disposal, air emissions
and other environmental matters, all zoning and other land use matters, and
utility availability, and with any direction of any public officer or officers,
pursuant to law, which shall impose any duty upon Lessor or Lessee with respect
to the use or occupation of the Premises.

     43.02     Use of Hazardous Materials

     (1) Lessee shall (1) not cause or permit any Hazardous Material to be
brought upon, kept or used in or about the Premises or the Project by Lessee,
its agents, employees, contractors, or invitees without the prior written
consent of Lessor, which Lessor shall not unreasonably withhold as long as
Lessee demonstrates to Lessor's reasonable satisfaction that such Hazardous
Material is necessary or useful to Lessee's business and will be used, kept and
stored in a manner that complies with all laws regulating any such Hazardous
Material so brought upon or used or kept in or about the Premises. If Lessee
breaches the obligations stated in the preceding sentence, or if the presence
of Hazardous Material on the Premises or the Project caused or permitted by
Lessee results in contamination of the Premises or the Project, or if
contamination of the Premises or the Project by Hazardous Material otherwise
occurs for which Lessee is legally liable for Lessor for damage resulting
therefrom, then Lessee shall indemnify, defend and hold Lessor harmless from
any and all claims, judgements, damages, penalties, fines, costs, liabilities
or losses (including, without limitation, diminution in value of the Premises
or the Project, damages for the loss or restriction on use of rentable or usable
space or of any amenity of the Premises or the Project, damages arising from
any adverse impact on marketing of space, and sums paid in settlement of
claims, attorneys' fees, consultant fees and expert fees) which arise during or
after the Lease term as a result of such contamination.
<PAGE>   16
This indemnification of Lessor by Lessee includes, without limitation, costs
incurred in connection with any investigation of site conditions or any
clean-up, remedial, removal or restoration work required by any federal, state
or local governmental agency or political subdivision because of Hazardous
Material present in the soil or ground water on or under the Premises or the
Project. Without limiting the foregoing, if the presence of any Hazardous
Material on the Premises or the Project caused or permitted by Lessee result in
any contamination of the Premises or the Project, Lessee shall promptly take
all actions at its sole expense as are necessary to return the Premises and the
Project to the condition existing prior to the introduction of any such
Hazardous Material to the Premises or the Project; provided that Lessor's
approval of such action shall first be obtained, which approval shall not
unreasonably withheld so long as such actions would not potentially have any
material adverse long-term or short-term effect on the Premises or the Project.
The foregoing indemnity shall survive the expiration or earlier termination of
this Lease.

     (2)  Definition of "Hazardous Material". AS used herein, the term
"Hazardous Material" means any hazardous or toxic substance, material or waste,
including, but not limited to, those substances, materials or wastes listed in
the United States Department of Transportation Hazardous Material Table (49 CFR
172.101) or by the Environmental Protection Agency as hazardous substances (40
CFR Part 302) and amendments thereto, or such substances, materials and wastes
that are or become regulated under any applicable local, state or federal law.

     (3)  Disclosure. At the commencement of this Lease, and on January 1 of
each year thereafter (each such date being hereafter called "Disclosure
Dates"), including January 1 of the year after the termination of this Lease,
Lessee shall disclose to Lessor the names and amounts of all Hazardous
Materials, or any combination thereof, which were stored, used or disposed of
on or about the Premises, or which Lessee intends to store, use or dispose of
on or about the Premises.

     (4)  Inspection. Lessor and its agents shall have the right, but not the
duty, to inspect the Premises and the Project at any time to determine whether
Lessee is complying with the terms of this Lease. If Lessee is not in compliance
with this Lease, Lessor shall have the right to immediately enter upon the
Premises and the Project and the to remedy any contamination caused by Lessee's
failure to comply notwithstanding any other provision of this Lease. Lessor
shall use its best efforts to minimize interference with Lessee's business but
shall not be liable for any interference caused thereby.

     (5)  Default. Any default under this Paragraph shall be a material default
enabling lessor to exercise any of the remedies set forth in this Lease.






<PAGE>   17
                               SPECIAL PROVISION



44.   USE CLAUSE

      44.01 Tenant has negotiated the use clause contained in section 1.05 of
this lease. Tenant hereby agrees that the use clause as so written is deemed to
be reasonable for all purposes. Tenant hereby further agrees that this use
clause is enforceable for all purposes and specifically waives all challenges
to this clause now and in the future. The purpose for which this use clause is
deemed to be reasonable and enforceable include, but are not limited to, any
and all future changes tenant may request in the use of the premises, and any
and all circumstances relating to breach of lease, and/or mitigation of
damages, and/or assignment, and/or subletting.

45.   SMOKING

      45.01 Smoking of any kind is strictly prohibited at all times at any
location on this property, except in the designated smoking area which is
located as follows:

Outside the perimeter of building only.

The designated smoking area may be relocated by Lessor at its sole discretion
at any time during the term of the Lease.

<PAGE>   18
PROVISION #46

                  Estimated Operating Costs and Property Taxes


Pursuant to provision 5, "Additional Rent", of this Lease, Lessee shall pay to
Lessor in addition to all expenses stated in this lease on a monthly basis, in
advance, in addition to Lessee's monthly base rent, the amount of Lessee's
estimated monthly Proportionate Share of Operating Cost and Property Taxes as
defined and calculated in accordance with and subject to the provisions of
Section 5.02, "Operating Cost", and Section 5.03, "Taxes", under this Lease.
At the inception of this Lease, Lessee's initial estimated monthly Proportionate
Share of Operating Costs and Real Property Taxes are estimated by Lessor to be
equal to Two thousand one hundred ninety eight dollars ($2,198.00).

<PAGE>   19
PROVISION #47

                   TELEPHONE OR TELECOMMUNICATION LINE ACCESS

Tenant acknowledges that there are finite number of telephone or
telecommunication lines available to the premises and the property. Tenant
further acknowledges that Landlord must be able to provide all tenants of the
property satisfactory telephone or telecommunication lines access in order to
provide telephone or communication access and service to all tenants. Therefore
tenant agrees that it will not apply for more than 49 telephone lines to its
premises, nor install any telephone, telecommunication or other communication
equipment (specifically including any antennas (lower or microwave) or other
exterior equipment of any nature) which either utilizes telephone equipment or
technology or in any other manner effects Landlord's ability to provide
telephone or communications facilities or access to its tenants other than as
listed hereon without the express written permission of Landlord. Tenant agrees
therefore that;

a.   Landlord Consent Required. In the event that Tenant wishes additional
     telephone, telecommunication or other communication lines or access after
     the date of Tenant's execution of this Lease, no such additional lines or
     access shall be permitted nor other telephone, telecommunication or
     communication related equipment installed without first securing the prior
     written consent of Landlord.

b.   Conditions to Consent. All of the following conditions must be met, as
     expressed in a written agreement between Tenant and Landlord or by any
     other means acceptable to Landlord in its reasonable judgment, before
     Landlord considers whether to give its consent or not:

     (1)  No Expense. Landlord shall incur no expense whatsoever with respect to
          any aspect of Tenant's need for additional access or equipment,
          including without limitation, the costs of installation, materials,
          permits, service, etc.

     (2)  Building Rules. Prior to the commencement of any work in or about the
          building to install such additional access, lines or equipment, Tenant
          shall agree to abide by such rules and regulations, job site rules,
          and such other requirements as reasonably determined by Landlord to be
          necessary to protect the interest of the building, the Tenants in the
          Building, and the Landlord, including without limitation, providing
          security in such form and amount as determined by Landlord;

     (3)  Sufficient Space. Landlord reasonably determines that there is
          sufficient space in the building for the placement of all of the
          lines, access and equipment.

     (4)  Tenant is not, nor has been at time during lease term, in breach or
          default under the lease.

     (5)  Compensation for Space. Tenant agrees to compensate Landlord the
          reasonable amount determined by Landlord for space used in the
          building for the storage and maintenance of the equipment, if any lies
          outsides the leased premises, and for all costs that may be incurred
          by Landlord in arranging for: access by the Tenant's personnel,
          security for Tenant's equipment, and any other such costs as Landlord
          may expect to incur.

c.   Consent is Not Landlord Warranty. Landlord's consent under this section
     shall not be deemed any kind of warranty or representation by Landlord,
     including without limitation, any warranty or representation as to the
     availability or suitability, of the present or future telephone or
     communications equipment, connections, compatibility or space available for
     any additional equipment, lines or access.

d.   Tenant Pays Expenses. Tenant acknowledges and agrees that all telephone and
     telecommunications services desired by Tenant shall be ordered and utilized
     at the sole expense of Tenant.

e.   Tenant Responsible for Service Interruptions. Tenant agrees that to the
     extent service by any telephone or communication equipment is interrupted,
     curtailed, or discontinued, Landlord shall have no obligation or liability
     with respect thereto and it shall be the sole obligation of Tenant at its
     expense to obtain substitute service, but only with Landlord's prior
     written permission.

f.   Landlord's Refusal to Consent. Notwithstanding any provision herein to the
     contrary, the refusal of Landlord to consent to any prospective request
     shall not be deemed a default or breach by Landlord of its obligation under
     this Lease unless and until Landlord is adjudicated in a final and
     unappealable court decision to have acted recklessly or maliciously with
     respect to its refusal.

g.   No Third Party Rights. The provisions of this clause may be enforced solely
     by the Tenant and Landlord, and are not for the benefit of another party,
     specifically, without limitation, no telephone or telecommunications
     provider shall be deemed a third part beneficiary of the Lease.

                 EQUIPMENT TO BE INSTALLED AT THE COMMENCEMENT
                                 OF THE LEASE.



<PAGE>   20
PROVISION #48


ADJUSTMENTS TO BASE MONTHLY RENT


The Base Monthly Rent shall be adjusted to the following amounts for the
following periods.

May 1, 1999 through November 30, 1999, Lessee's Base Monthly Rent shall
increase to Nine thousand eighty nine dollars ($9,089.00) per month.

December 1, 1999 through November 2000, Lessee's Base Monthly rent shall
increase to Nine thousand four hundred ninety one dollars ($9,491.00) per month.

December 2000, through October 31, 2001, Lessee's Base Monthly rent shall
increase to Nine thousand nine hundred ninety dollars ($9,990.00) per month.

<PAGE>   21
PROVISION #49

OPTION TO RENEW

Provided that Lessee is not in default or breach of the terms and conditions of
the within Lease, Lessee is hereby granted a one time (1) Option to Renew this
Lease for an additional period of one (1) year.

All such terms, conditions and rental provisions shall, upon the exercise of
the option, be evidenced upon the form of the Lease then in effect for the
project. The within option shall be exercised by Lessee no later than four (4)
months prior to the expiration of the initial term of the within Lease.

Should Lessee exercise the above option to renew, the base monthly rent for the
renewal term shall increase to reflect the prevailing fair market rental rate.
For the purpose of the lease the term "Fair Market Rental Rate" shall mean the
monthly amount per rentable square foot that Lessor has accepted in current
transactions between non-affiliated parties from new, non-expansion,
non-renewal tenants of comparable credit worthiness, for comparable space, for a
comparable use, for a comparable period of time, in the building. If the Lessor
and Lessee cannot agree on the fair market rent for the premises.

In the event Lessee or Lessor  are unable to agree to the terms and conditions
to such renewed term within six (6) months prior to the expiration for the
initial term the parties hereto shall have no further obligation hereunder.


<PAGE>   22
PROVISION #50


OPTION TO EXPAND:

Provided that Lessee is not in default of any term or condition of any lease or
has not been in default of any lease at 6450 Lusk Blvd., Lessor agrees to the
following

NON RENEWAL OF EXISTING TENANT

1     With notice to PS Business Parks, Inc., on or before January 1, 1999,
      WebSideStory will have the option to lease E201 & 202 from May 1, 1999
      through October 31, 2001. The rental rate will be the then prevailing
      market rate.

2.    With notice to PS Business Parks on or before March 1, 1999, WebSideStory
      will have the option to lease E209 from July 1, 1999 through October 31,
      2001. The rental rate will be the then prevailing market rate.


PROJECT PLAN

3.    With ninety (90) day notice to PS Business Parks, Inc., WebSideStory, Inc.
      will have the option to lease E200, (provided PS Business Parks has a
      space suitable for a Conference Center) for a twenty (20) month period or
      until October 31, 2001, whichever is longer. Rent will be the then
      prevailing market rate.

4.    With ninety (90) day notice to PS Business Parks, Inc., WebSideStory,
      Inc., will have the option to lease suites E210 & E105 (Pursuant to
      paragraph 32.01, PROJECT PLAN).  WebSideStory, Inc., will be responsible
      for all costs that PS Business Parks is required to pay pursuant to the
      project plan clause in connection with the moving of existing tenants to
      another space within the project provided similar space is available.

5.    All new expansions will have the same terms and conditions as this lease
      dated November 4, 1998.

6.    WebSideStory, Inc., agrees to pay for all costs incurred to re-divide the
      suites upon vacating during the term of any lease or upon expiration of
      lease term.










<PAGE>   23
                                 PROVISION #51

                               LEASE MODIFICATION

This agreement is entered into between PS Business Parks, Inc. hereinafter
referred to as "Lessor" and WEBSIDESTORY, INC., A California Corporation,
referred to as "Lessee" in this agreement.

                                    Recitals

The Lessor and Lessee entered into a written lease, referred to in this
agreement as the "Lease", beginning December 1, 1998 for the premises commonly
known as 6450 Lusk Blvd., Suites E103.104, 203, 204, 207, & 208, San Diego, CA
92121. The Lease is attached to this agreement as Exhibit A and is incorporated
by reference.

Lessor and Lessee desire to amend the lease and therefore, it is agreed:

For valuable consideration, receipt and sufficiency of which is acknowledged by
the parties, the following amendment is added to the Lease:

Lessor herein grants to Lessee, subject to the terms and conditions below, at
Lessee's sole cost, permission to construct and maintain one (1) back-up
generator located at the exterior of the Premises as indicated on Exhibit B
attached. Specifications and dimensions of the back-up generator and all
connections, utility and otherwise (including all power sources) are listed on
Exhibit C, attached hereto. Lessee agrees that said back-up generator will:

     (1)       Be approximately:  Length:  92 inches, Width:  43 inches, Height:
          64 inches.

     (2)       Weight including attachments approximately 2,500 pounds.

     (3)       Be enclosed within chain link fence and shrouded from view at
          least 8 feet high, rest on a 10' by 10' concrete pad and be locked at
          all times it is not being serviced.

     (4)       There can be no building penetration other than for an electrical
          line. Any building penetration must be pre-approved by Lessor.

     (5)       Be in compliance with (including compliance with the Certificate
          of Occupancy requirements of the City of San Diego) all applicable
          laws, ordinances, codes, etc. that may be imposed on the construction
          and continued operation of the back-up generator.

     (6)       Have all construction; architectural plans, utility connection
          and other installation and operation requirements approved, in
          advance, in writing by Lessor.

Lessee agrees that it will carry additional liability insurance of
$300,000.00/$500,000.00 covering any and all damage whether by acts of God,
negligence or otherwise, caused directly or indirectly by the back-up generator,
its stands, support, etc. The policy issuer of this policy shall notify Lessor
thirty (30) days prior to the expiration or the termination of the policy.
Failure of Lessee to provide proof of insurance beyond the termination or
expiration date, three days prior to such termination or expiration date, shall
give Lessor the unqualified right to remove the back-up generator with no
liability of Lessors part regardless of any damage thereof.

Lessee agrees that it will indemnify and hold harmless Lessor from any damage
cause by the back-up generator.
<PAGE>   24
Lessee agrees that it will, at its sole cost, maintain and keep in good repair
and condition (in Lessor's sole opinion) the generator, the fence, and all
supports and connections (herein after "back-up generator") during the Lease.
Lessor and its agents shall have the right, but not the duty, to inspect the
back-up generator any time to determine whether Lessee is complying with the
terms of this Lease. If Lessee is not in compliance with this section of the
Lease, Lessor shall have the right, after giving Lessee notice and an
opportunity to cure any such default, to immediately enter upon the Premises
and back-up generator location to remedy the violation of this section of the
Lease including but not limited to removal of the back-up generator. Any
default under this paragraph shall be a material default enabling Lessor to
exercise any of the remedies set forth in the Lease.

Lessee agrees that it shall be responsible for removal of the back-up
generator, pad, fencing, etc. and any and all related equipment, at Lease
termination or earlier if demanded by Lessor. Lessee further acknowledges that
it will be responsible for returning the area, all penetrations to the building
be virtue of such back-up generator and the Premises if applicable in Lessor's
sole opinion to its original condition to Lessor's sole satisfaction.

As additional consideration for the placement of the back-up generator lessee
agrees to the additional rental of $200.00 per month.

Except for the modification of the Lease made herein, all provisions of the
Lease shall continue in full force and effect.

This modification shall become effective on 12/01/98.


LESSOR                              LESSEE

PS Business Parks, Inc.             WEBSIDESTORY, INC.,
A California Corporation               A California Corporation
By its agent
PS Business Parks, L.P.,
By: PS Business Parks, Inc.
    General Partner


By: /s/ [SIGNATURE ILLEGIBLE]       By: /s/ [SIGNATURE ILLEGIBLE]
   -----------------------------       ------------------------------

--------------------------------

Date:   12/7/98                     Date:
     ---------------------------         ----------------------------

--------------------------------






                                  Page 2 of 2
<PAGE>   25
                                   EXHIBIT A

                         [SITE MAP GENERATOR LOCATION]

                     PS BUSINESS CENTER - SORRENTO MESA III

         6370, 6440, 6450, LUSK BOULEVARD, SAN DIEGO, CALIFORNIA 92121
<PAGE>   26
                            [DIAGRAM OF FLOOR PLAN]

                         PS BUSINESS CENTER - LUSK III
                                SUITE E207-E208

                              6450 LUSK BOULEVARD
                                   BUILDING E
                              SAN DIEGO, CA 92121
<PAGE>   27
                            [DIAGRAM OF FLOOR PLAN]

                         PS BUSINESS CENTER - LUSK III
                                SUITE E203-E204

                              6450 LUSK BOULEVARD
                                   BUILDING E
                              SAN DIEGO, CA 92121

                                                                 Suite E203-E204
<PAGE>   28





                            [DIAGRAM OF FLOOR PLAN]






                         PS BUSINESS CENTER - LUSK III



6450 LUSK BOULEVARD
BUILDING E                                                    SUITE E104
SAN DIEGO, CA 92121





<PAGE>   29

                            [DIAGRAM OF FLOOR PLAN]


                         PS BUSINESS CENTER - LUSK III



6450 LUSK BOULEVARD
BUILDING E                                                    SUITE E103
SAN DIEGO, CA 92121





<PAGE>   30
                                   EXHIBIT A

                               LEGAL DESCRIPTION

     THE REAL PROPERTY SITUATED IN THE STATE OF CALIFORNIA, COUNTY OF SAN
DIEGO, AND IS DESCRIBED AS FOLLOWS:

LOTS 4 AND 5 OF LUSK INDUSTRIAL PARK UNIT NO. 5, IN THE CITY OF SAN DIEGO,
COUNTY OF SAN DIEGO, STATE OF CALIFORNIA, ACCORDING TO MAP THEREOF, NO. 10700,
FILED IN THE OFFICE OF THE COUNTY RECORDER OF SAN DIEGO COUNTY, AUGUST 16,
1983.

EXCEPT THEREFROM ALL COAL, OIL, GAS, PETROLEUM AND OTHER HYDROCARBON SUBSTANCES
IN AND UNDER SUCH PROPERTY, GRANTOR, ITS SUCCESSORS AND ASSIGNS, RETAINING THE
EXCLUSIVE TITLE AND RIGHT TO REMOVE SAID SUBSTANCES, TOGETHER WITH SOLE RIGHT TO
NEGOTIATE AND CONCLUDE LEASES AND AGREEMENT WITH RESPECT TO ALL SUCH SUBSTANCES
UNDER THE PROPERTY, AND TO USE THOSE PORTIONS OF THE PROPERTY WHICH UNDERLIE A
PLANE PARALLEL TO, AND 500 FEET BELOW, THE PRESENT SURFACE OF THE PROPERTY FOR
THE PURPOSE OF PROSPECTING FOR, DEVELOPING AND/OR EXTRACTING SUCH SUBSTANCES
FROM THE PROPERTY BY MEANS OF WELLS DRILLED INTO OR THROUGH SAID PORTIONS OF
THE PROPERTY FROM DRILL SITES LOCATED ON OTHER PROPERTY, IT BEING EXPRESSLY
UNDERSTOOD AND AGREED THAT GRANTOR, ITS SUCCESSORS AND ASSIGNS SHALL HAVE NO
RIGHT TO ENTER UPON THE SURFACE OR THE PROPERTY OR ANY PORTION THEREOF ABOVE
THE LEVEL OF THE AFORESAID PLANE, AS RESERVED BY LUSK/MIRA MESA, A LIMITED
PARTNERSHIP, IN A DEED RECORDED FEBRUARY 18, 1984, RECORDER'S FILE NO.
84-058807.




                                  PAGE 2 OF 2
<PAGE>   31
                                  EXHIBIT "B"

Lessee accepts premises in present condition.

Subject to the provisions of Article 9, Lessee accepts the premises in the
condition they are in at the commencement of this lease and shall maintain said
premises in the same condition, order, and repair, excepting only reasonable
wear and tear, arising from the use under this Agreement. Lessee has examined
and knows the condition of the leased premises and agrees that no
representation, except such as are contained herein, have been made to Lessee
respecting the condition of said premises. The taking possession of said
premises by Lessee shall be conclusive that the premises are in good and
satisfactory condition.

Lessor agrees to clean carpeting and paint suite throughout in suite E103.
<PAGE>   32
TENANT SIGN CRITERIA

Type style: Helvetica Medium, All caps or upper and lower case.

-------------------------------------------------------------------------------
abcdefghijklmnopqrstuvwxyz
ABCDEFGHIJKLMNOPQRSTUVWXYZ
-------------------------------------------------------------------------------
Material: Die-cut letters.

Color: Black or White - According to building standard.

Size: see illustrations.

Mounting Location: To remain consistent with sign criteria.


                                   [DIAGRAM]

Note: No sign submittal will be considered if more than 40% of allowable sign
area is utilized for positive copy. All sign requests must be submitted on
scaled drawings for written approval by Lessor.

For additional information, please contact the Operations Manager located in
our Leasing Office.








EXHIBIT "C"

<PAGE>   33
TENANT DOOR SIGNAGE


      ---------------------------------------
1 1/2"                                                (Suite Number)
      ---------------------------------------


  3"


      ---------------------------------------
1 1/2"                                                (Tenant Name)
      ---------------------------------------


      ---------------------------------------
1 1/2"
      ---------------------------------------


      ---------------------------------------
1 1/2"
      ---------------------------------------


                                   [DIAGRAM]


                                   [DIAGRAM]










EXHIBIT "C"
<PAGE>   34
                                  EXHIBIT "D"

                             RULES AND REGULATIONS

In order to promote the safety, cleanliness, and aesthetics of the business
park, the following rules and regulations are in effect which may be modified or
amended at any time by Lessor upon notice to Lessee. In the case of conflict
between these regulations and the Lease, the Lease shall be controlling.

1.   Furniture, safes/moving. Safes, furniture, or bulky articles shall be moved
in and out of the complex in a manner and at such times so as not to create an
inconvenience to other tenants and is subject to direction and approval of
Lessor. Heavy articles that exceed the structural support of the premises or
exceeds fifty (50) pounds per square foot is not permitted. Any heavy articles
which exceeds load capacity of the elevator to transport it is not permitted.

2.   Windows/signs. All tenant identification signs shall be a type, size, and
color as specified by Lessor and provided at Lessee's expense. No sign, picture,
or advertisement may be placed in the windows, common areas or exterior of the
building. Where Lessor provides standard window coverings, such coverings shall
not be altered, removed or replaced by Lessee. Where Lessor does not provide
standard window coverings, installation of window coverings by Lessee shall be
subject to Lessor's prior written approval.

3.   Common area/roof. Sidewalks, common area hallways, stairwells, elevators,
entrances, and exits shall not be obstructed or used by Lessee for any purpose
other than normal ingress and egress. Neither Lessee nor employees or invitees
of Lessee shall go upon the roof of any building.

4.   Parking. The parking areas include surface parking, parking structure,
driveways, entrances, exits, pedestrian walkways, and any other areas designated
for parking and shall be regulated and modified by Lessor with respect to
restricted areas, direction and flow of traffic, hours of use, and any other
related facilities. The parking areas shall be used solely for the parking of
passenger vehicles during normal business hours. The parking of trucks,
trailers, recreational vehicles, and campers is not permitted. No vehicle of any
type shall be stored in the parking areas at any time. In the event that a
vehicle is disabled it shall be removed within 48 hours. Maintenance of vehicles
is not permitted in the parking areas. All vehicles shall be parked in
designated parking areas in conformance with all signs and markings and shall
not be parked in areas not designated for parking, in aisles, driveways,
no-parking areas, or in any manner which impedes the flow of traffic. "For Sale"
signs or any other advertising is not permitted on or about any parked vehicle.
Lessor may implement a validation system or other proration with or without
charges to Lessee and/or other users for use of the parking area.

5.   Vendors. Lessor reserves the right to prohibit personal goods and service
vendors from access to the building as are related to the safety, care, and
cleanliness of the building and the relief of any financial burden on Landlord
created by the presence of such vendors.

6.   Advertising. Lessee shall not use the name of the building in connection
with promoting or advertising Lessee's business except as to Lessee's address.
Lessor shall have the right to prohibit the use of the name of the project or
other publicity by Lessee which in Lessor's opinion tends to impair the
reputation of the project or its desirability for other Lessees. Lessee will
discontinue such publication immediately upon receipt of notice from Lessor.

7.   Dangerous articles. Lessee shall not use or keep on the premises or any
part of the project any kerosene, gasoline, or inflammable or combustible fluid
or material or any article deemed extra hazardous.



                                  Page 1 of 3
<PAGE>   35
8.    Nuisance.  Lessee shall not keep or allow to be used any foul or noxious
gas of substance on the premises. Nor shall Lessee occupy or use the premises
in any manner which is objectionable or offensive to other occupants by reason
of odor, notice, vibration, or interference in any way with other tenants or
those having business therein. No animals or birds shall be brought in or kept
about the premises or any part of the project. Lessee shall maintain the leased
premises free of mice, ants, bugs, or other vermin.

9.    Improper conduct.  Lessor reserves the right to expel from the business
park any person who is intoxicated or under the influence of liquor or drugs or
who shall act in violation of any of these rules and regulations.

10.   Janitorial service.  Lessee shall not dispose any dirt or other substance
into the parking areas, landscaping, walkways, or common areas. Lessee shall
not do any act which would create additional costs to maintain the cleanliness
of the project. Lessor shall not be responsible to Lessee for  loss of property
on the premises or for any damage done by the janitorial service, employee, or
any other person.

11.   Building access.  Lessee may have access to the building and premises
between the hours of 8:00 am and 6:00 pm Monday through Friday. Lessor reserves
the right to refuse access to the building in the case of invasion, riot, mob,
or other commotion for safety of the tenants and protection of property. Lessor
shall not be liable for damages for the admission or exclusion of any person
from the building. If Lessee uses the building after regular hours or on
non-business days, Lessee shall keep all entrance doors to the building locked
immediately after entering or leaving the building.

12.   Heating/air conditioning. Lessor shall be under no obligation to provide
heating or air conditioning services to the building between the hours of 6:00
pm and 8:00 am and on non-business days. Lessee may request Lessor to provide
additional heating or air conditioning during off hours or non-business days
and should Lessor provide the additional service, Lessor may determine the
costs incurred which Lessee will pay to Lessor. Lessee shall not use any method
of heating or air conditioning other than supplied by Lessor.

13.   Locks.  Lessee shall not alter any lock or install new or additional lock
or bolt on any door of the premises without prior written consent of Lessor. If
Lessor shall give such consent, Lessee shall furnish a key to such lock. Upon
termination of the tenancy, Lessee must return all keys of the premises to
Lessor.

14.   Rest Rooms.  The restrooms and facilities shall not be used for any
purposes other than those for which they were constructed. No dirt, trash, or
other foreign substances shall be disposed of therein. No person shall waste
water or tamper with faucets or fixtures. Any damage caused by Lessee, his
employees, agents, or invitees shall be paid for by the Lessee.

15.   Requirements of Lessee.  Employees of Lessor shall not perform any work
or do anything outside of their regular duties unless under special instruction
from Lessor. Lessee shall give prompt notice of required maintenance items,
for which Lessor is responsible within the leased premises. Lessee shall give
Lessor prompt notice of any defects in the water, sewage, gas pipes, exterior
electrical lights and fixtures, or other service equipment.

16.   Solicitation. Lessee shall not disturb, solicit, or canvas any occupant
of the project and shall cooperate to prevent the same.



                                  Page 2 of 3

<PAGE>   36
17.   Use of premises.  The leased premises shall not be used for lodging,
sleeping, cooking, or for any immoral or illegal purpose or for any purpose
that will damage the premises or the reputation thereof.  Lessee shall not use
the premises for any purpose other than that specified in the lease covering
the premises.

18.   Safety.  Lessee shall not do or permit any act or bring anything on the
premises which shall in any way increase rate of fire insurance on the
building, obstruct or interfere with, the right of other tenants, conflict with
fire regulations and fire laws, or conflict ordinances established by the Board
of Health or other governmental authority.

19.   Auction.  No auction, public or private, will be permitted.

20.   Damage.  Walls, floors and ceilings shall not be defaced in any way and
no one shall be permitted to make, paint, penetrate or in any way mar the
building surfaces, walkways, stairwells, driveways, or parking area. Pictures,
certificates, licenses, and similar items normally used in Lessee's premises
may be carefully attached to the walls by Lessee in a manner to be prescribed
by the Lessor. Upon removal of such items by Lessee, any damage to the walls or
other surfaces shall be repaired by Lessee.

21.   Wiring.  No electrical wiring, electrical apparatus, or additional
outlets shall be installed without the prior written approval of Lessor. Any
such installation may be removed by Lessor at Lessee's expenses. Lessee may not
alter any existing electrical outlets or overburden them beyond their designed
capacity. Lessor reserves the right to enter the leased premises, with
reasonable notice to tenant, for the purpose of installing additional
electrical wiring and other utilities for the benefit of Lessee or adjoining
tenants. Lessor will direct electricians as to where and how telephone and
telegraph wires are to be introduced. The location of telephones, call boxes,
and other equipment affixed to the premises shall be subject to the approval of
Lessor.

22.   Exteriors. Lessee shall not place any improvement or moveable object
including antennas, awnings, outside furniture, etc. in the parking areas,
landscape areas, on the roof, or other areas outside of the leased premises.

23.   General.  It is understood that if Lessee, his employees, agents, or
invitees violate any of these rules and regulations which results in any damage
to the property, increases costs of maintenance of the property, or incurs
expenses to reasonably enforce the rules and regulations, Lessee shall pay to
Lessor all such costs as additional rent.



                                  Page 3 of 3

<PAGE>   37

                              RULES AND REGULATIONS
                  FITNESS CENTER & CONFERENCE CENTER AGREEMENT

This supplemental agreement, dated November 4, 1998 is entered into between PS
Business Parks, Inc., A California Corporation hereinafter referred to as
"Lessor" and, PS Business Parks, Inc. WebSideStory, Inc., hereafter referred to
as "Lessee" (which shall hereinafter refer to and include, but not limited to,
Lessee, Lessee's employees, and Lessee's visitors) in this agreement. The Lessor
and Lessee entered into a written lease, referred to in this agreement as the
"Lease", on December 1, 1998 for the Premises located at 6450 Lusk Blvd., Suites
E103, 104, 203, 204, 207, 208.

RULES AND REGULATIONS AS SET FORTH ARE PART OF THE LEASE AND LESSEE, ITS
EMPLOYEES AND VISITORS ARE OBLIGATED TO OBSERVE AND COMPLY WITH THE SAME. LESSOR
MAY MAKE REASONABLE CHANGES FROM TIME TO TIME WITHOUT PRIOR APPROVAL BY LESSEE.

A portion of the Common Areas shall include a Fitness Center and Conference
Center, hereinafter referred to as "Centers". Use of the Centers shall be open
to Lessee during normal business hours, or such other hours as Lessor may
reasonably determine. Lessor will not provide any staff to monitor or supervise
the use of the Centers. Use of the Centers shall be solely at the risk of the
individual using the Centers facilities, and Lessor shall have no responsibility
for Lessee who shall use the Centers. In the event that Lessor suffers any loss
arising out of the use of the Centers by Lessee, said Lessee shall indemnify
Lessor for any such loss. Lessee agrees to abide by such reasonable rules and
regulations as Lessor may promulgate from time to time concerning use of the
Centers. Lessor, at its sole discretion, shall have the right to revoke Lessee's
privileges should Lessee cause damage, abuse or violate any of the rules and
regulations in this agreement or posted within the Centers. Lessee shall also be
solely responsible to reimburse Lessor for any damage caused by Lessee. Access
to the Centers shall be controlled by means selected by Lessor. The Fitness
Center's use is limited to Lessee and its employees only and may only be
accessed by Lessee's visitors when accompanied by Lessee. Lessor shall have the
right to request, from time to time a list of Lessee's employees for the
purposes of controlling unauthorized access to the Centers. Lessee shall notify
Lessor when any of Lessee's employees terminate employment. Initial issuance of
keys or other devices for controlling access to the Centers shall be at $15.00
per card to Lessee, but Lessor reserves the right to impose a reasonable charge
to replace, repair and/or maintain equipment, furniture, access devises or any
other furnishings pertinent to the Centers.

In accordance with the paragraphs of your Lease referring to BASE MONTHLY RENT
and ADDITIONAL RENT, If Base Monthly Rent or any Additional Rent is not paid per
your Lease Agreement, Lessor, in its sole discretion, shall have the right to
suspend and/or revoke all Fitness and Conference Center privileges without
further notice and access will be terminated. If Lessee's privileges are
suspended or revoked, Lessee shall still be obligated to pay their pro rata
share, and will receive no reduction or modification of common area maintenance
fees. Reinstatement of Fitness and Conference Center privileges, which is at all
times in the sole
<PAGE>   38
discretion of Lessor, may be requested in writing by any suspended or revoked
Lessee. In addition to any and all moneys due and owing under the Lease, $25.00
per each person reinstated will be charged.

1.   HOURS: Normal business hours for the Centers will be posted within the
Centers and shall be subject to reasonable change at the sole discretion of
Lessor. Should Lessee request use of the Centers anytime other than during
normal business hours, Lessor, at its sole discretion, reserves the right to
grant Lessee's request and Lessor also reserves the right to charge Lessee
$35.00 per hour for such use.

2.   ACCESS: Lessee will be issued key/s, access card/s or access code/s, at
$15.00 per card, to the Fitness Center. Lessee shall reserve in advance, on a
first come first serve basis with Lessor, the day and time they would like to
reserve the Conference Center. Lessee agrees that use of their key, access card
or code number by anyone other than to whom it was issued could result in the
Centers being closed to said Lessee and all access keys, cards, and codes
confiscated. Lessor reserves the right to issue new access keys, cards or codes.

3.   USE OF CENTERS FACILITIES: In order to insure that the Centers are
properly maintained, Lessor reserves the right to temporarily close or limit
access to the Centers at any time during the year. Lessor may close the Centers
on legal holidays, open houses or other promotions. Lessee acknowledges and
agrees that alcoholic beverages, illegal drugs, smoking and/or chewing tobacco
is prohibited in both Fitness and Conference Centers. Lessee is responsible for
the disposal of all food, trash and other items brought into or used within the
Center and Lessor shall not be responsible for the clean up during normal
business hours.

4.   FACILITY RULES: Lessee will, at all times, make sure that the doors to the
Fitness Center, Conference Center, Bathrooms and Showers remain closed while in
use. All users must provide their own towel and dry off before leaving the
shower area. Lockers are provided on a per visit basis and Lessor is not
responsible for lost, stolen or damaged items. Locks left on lockers overnight
will be cut off and contents donated to charity or discarded. Lessee
acknowledges and agrees that Lessor, its officers, agents and employees, will
not be liable for either loss or damage to Lessee's property or personal
possessions within or on the Centers premises, including but not limited to the
parking facilities.

5.   FITNESS CENTER: Lessee must carry a towel at all times while using the
equipment and/or machinery and will wipe clean all sweat after the use of
equipment and/or machinery. Any person using equipment or machinery shall be
familiar with the proper usage and operation prior to such use. It is the sole
duty of Lessee to check and confirm proper functioning of equipment and/or
machinery prior to any use; Lessor is not responsible for any malfunction,
disrepair, breakage, misuse, or any claim of injury or loss therefrom. Lessee
hereby agrees that they are voluntarily participating in physical exercise and
should use common sense, only the individual can monitor his or her own
personal physical feelings. Immediately stop any sports activity if you feel
faint, dizzy, nauseous, or short of breath. Lessor makes no warranties
<PAGE>   39
and no representations express or implied, other than those set forth herein and
Lessee acknowledges and agrees that they have not relied on any warranties or
representations other than those set in this Rules and Regulations. Lessee is
aware that participation in a sport or physical exercise may result in accidents
or injury, and Lessee assumes the risk connected with the participation in a
sport or exercise represents that Lessee is in good health and suffers from no
physical impairment, disability or ailment preventing Lessee from safety,
comfort, or physical condition, or to that of others. It is advisable that
Lessee consult their physician before undertaking the use of fitness equipment
and/or machinery. Lessee acknowledges that Lessor has not and will not render
any medical services including medical diagnosis of Lessee's physical condition.

6.   INDEMNIFICATION AND WAIVER OF CLAIMS:   Lessee waives all claims against
Lessor for damage and/or loss to any real or personal property in or about the
Centers, Property, Project or Premises and for injury to any person, including,
but not limited to, death resulting therefrom, regardless of cause or time of
occurrence. Lessee will defend, indemnify and hold Lessor harmless from and
against all claims, actions, proceedings, expenses; damages and liabilities,
including attorney's fees, arising out of, connected with, or resulting from any
use of the Centers, Property, Project and Premises including and to any personal
property in or about the Centers, Property, Project and Premises by Lessee,
except for any damage or injury which is the direct result of intentional acts
by Lessor, its employees, agents, visitors or licenses.

<TABLE>
<S>                                          <C>
LESSOR                                       LESSEE
PS Business Parks, Inc.                      WebSideStory, Inc.
A California Corporation                     A California Corporation
----------------------------------------     -----------------------------------

By:  /s/ Patricia Abbott                     By:  /s/ Blaise Barrelet
     -----------------------------------          ------------------------------
Title:  Patricia Abbot, Regional Manager     Title:  Blaise Barrelet, President
        --------------------------------             ---------------------------
Date:  12/7/98                               Date:
       ---------------------------------            ----------------------------

                                             By:
                                                  ------------------------------
                                             Title:
                                                     ---------------------------
                                             Date:
                                                    ----------------------------

</TABLE>

NOTE:  Scheduling limitations for Corporate Conference Room

MAXIMUM HOURS per week/per tenant:            5 hours
MAXIMUM HORSE per month/per tenant:          20 hours
MAXIMUM DAYS tenant may schedule in advance: 30 days

Tenant may not schedule the same time consecutively throughout the month.