Document:

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                                                                     Exhibit 4.2

                          REGISTRATION RIGHTS AGREEMENT

     THIS REGISTRATION RIGHTS AGREEMENT (this "Agreement") is dated as of the
18th day of June, 1999, by and among WebSideStory, Inc., a California
corporation (the "Company"), and the persons designated as Investors on the
signature pages hereto and any permitted assignees thereof (each, an "Investor"
and collectively, the "Investors").

     WHEREAS, the parties to this Agreement are simultaneously entering into a
certain Stock Purchase Agreement, dated as of the date hereof (the "Purchase
Agreement"), whereby the Investors have agreed to purchase (i) shares of
Convertible Redeemable Participating Preferred Stock of the Company
("Convertible Stock"), which are convertible into shares of Common Stock of the
Company, and (ii) shares of Redeemable Preferred Stock of the Company
("Redeemable Stock"); and

     WHEREAS, the execution of this Agreement is an inducement and a condition
precedent to the purchase by the Investors of the shares of Convertible Stock
and the shares of Redeemable Stock under the Purchase Agreement.

     NOW, THEREFORE, in consideration of the premises, as an inducement to the
Investors to consummate the transactions contemplated by the Purchase Agreement,
and for other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the Company and the Investors hereby covenant and
agree with each other as follows:

     1. Certain Definitions. As used in this Agreement, the following terms
shall have the following respective meanings:

         "Board of Directors" means the Board of Directors of the Company.

         "Commission" shall mean the United States Securities and Exchange
Commission, or any other federal agency at the time administering the Securities
Act and the Exchange Act.

         "Common Stock" shall mean the common stock of the Company and any other
securities into which or for which such common stock may be converted or
exchanged pursuant to a plan of recapitalization, reorganization, merger, sale
of assets or otherwise.

         "Company" shall refer to the Company and any successor or successors
thereto.

         "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended, or any similar successor federal statute, and the rules and regulations
of the Commission thereunder, all as the same shall be in effect at the time.

         "Majority Interest" means the Investors holding not less than a
majority in interest in the outstanding Registrable Securities held by all
Investors.

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         "Person" shall mean an individual, a corporation, a partnership, a
joint venture, a trust, an unincorporated organization, a limited liability
company or partnership, a government and any agency or political subdivision
thereof.

         "Registrable Securities" shall mean (i) any shares of Common Stock
received by the Investors, or subject to acquisition by any Investor upon
conversion of the Convertible Stock (it being understood that for purposes of
this Agreement, a Person will be deemed to be a holder of Registrable Securities
whenever such Person has the right to then acquire or obtain from the Company
any Registrable Securities, whether or not such acquisition has actually been
effected) and (ii) any other securities issued and issuable with respect to any
such shares described in clause (i) above by way of a stock dividend or stock
split or in connection with a combination of shares, recapitalization, merger,
consolidation or other reorganization; provided, however, that notwithstanding
anything to the contrary contained herein, "Registrable Securities" shall not at
any time include any securities (i) registered and sold pursuant to the
Securities Act, (ii) sold to the public pursuant to Rule 144 or (iii) which
could then be sold in their entirety pursuant to Rule 144(k) without limitation
or restriction.

         "Registration Expenses" shall mean the expenses so described in Section
6 hereof.

         "Rule 144" shall mean Rule 144 promulgated under the Securities Act (or
any comparable successor rules).

         "Securities Act" shall mean the Securities Act of 1933, as amended, or
any similar successor federal statute, and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.

     2. Demand Registrations.

         (a) At any time after the first anniversary of the date hereof, a
Majority Interest of the Investors may notify the Company that they intend to
offer or cause to be offered for public sale all or any portion of their
Registrable Securities (representing offering proceeds aggregating not less than
$20 million for an initial public offering or $10 million otherwise) in the
manner specified in such request. Upon receipt of such request, the Company
shall promptly deliver notice of such request to all Persons holding Registrable
Securities who shall then have thirty (30) days to notify the Company in writing
of their desire to be included in such registration. If the request for
registration contemplates an underwritten public offering, the Company shall
state such in the written notice and in such event the right of any Person to
participate in such registration shall be conditioned upon their participation
in such underwritten public offering and the inclusion of their Registrable
Securities in the underwritten public offering to the extent provided herein.
The Company will use its reasonable best efforts to expeditiously effect the
registration of all Registrable Securities whose holders request participation
in such registration under the Securities Act and to qualify such Registrable
Securities for sale under any state blue sky law; provided, however, that the
Company shall not be required to effect registration pursuant to a request under
this Section 2 more than two (2) times for the holders of the Registrable
Securities as a group. Notwithstanding anything to the contrary contained
herein, if the Company receives a request for registration under this Section 2,
then (i) the Company may advise the requesting Investors, within fifteen (15)
days of its receipt of such request, that it

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intends to file a registration statement for the primary issuance of securities
in an underwritten public offering, and (ii) assuming that the Company files
such registration statement within seventy-five (75) days of its receipt of such
request, the Company's registration obligations under this Section 2 shall not
apply with respect to such request and no additional request may be made under
this Section 2 within one hundred eighty (180) days after the effective date of
such registration statement. In addition, the Company may postpone the filing or
the effectiveness of any registration statement pursuant to this Section 2 for a
reasonable time period, provided that such postponements shall not exceed one
hundred twenty (120) days in the aggregate during any twelve (12) month period,
if (i) the Company has been advised by legal counsel that such filing or
effectiveness would require disclosure of a material financing, acquisition or
other corporate transaction or development, and the Board of Directors of the
Company determines in good faith that such disclosure is not in the best
interests of the Company and its stockholders or (ii) the Board of Directors of
the Company determines in good faith that there is a valid business purpose or
reason for delaying filing or effectiveness. A registration will not count as a
requested registration under this Section 2(a) until the registration statement
relating to such registration has been declared effective by the Commission at
the request of the initiating holders; provided, however, that, if a Majority
Interest of the participating holders of Registrable Securities shall request,
in writing, that the Company withdraw a registration statement which has been
filed under this Section 2(a) but not yet been declared effective, a majority in
interest of such holders may thereafter request the Company to reinstate such
registration statement, if permitted under the Securities Act, or to file
another registration statement, in accordance with the procedures set forth
herein.

         (b) If a requested registration pursuant to Section 2(a) involves an
underwritten public offering and the managing underwriter of such offering
determines in good faith that the number of securities sought to be offered
should be limited due to market conditions, then the number of securities to be
included in such underwritten public offering shall be reduced to a number
deemed satisfactory by such managing underwriter, provided that the shares to be
excluded shall be determined in the following sequence: (i) first, securities
held by any other Persons (other than the Investors holding Registrable
Securities) not having either registration rights or contractual, incidental
"piggy back" rights to include such securities in the registration statement,
(ii) second, shares sought to be registered by the Company, (iii) third,
Registrable Securities of holders who did not make the original request for
registration, and (iv) fourth, Registrable Securities of holders who requested
such registration pursuant to Section 2(a), it being understood that no shares
shall be registered for the account of the Company or any shareholder other than
the Investors unless all Registrable Securities for which Investors have
requested registration have been registered. If there is a reduction of the
number of Registrable Securities pursuant to clauses (i), (iii) or (iv), such
reduction shall be made on a pro rata basis (based upon the aggregate number of
shares of Common Stock or Registrable Securities held by the holders in each
tranche and subject to the priorities set forth in the preceding sentence).

         (c) With respect to a request for registration pursuant to Section 2(a)
which is for an underwritten public offering, the managing underwriter shall be
chosen by the Investors holding not less than a Majority Interest of the
Registrable Securities to be sold in such offering, subject to the Company's
consent, which consent shall not be unreasonably withheld. The Company may not
cause any other registration of securities for sale for its own account (other
than a registration effected solely to implement an employee benefit plan or a
transaction to

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which Rule 145 of the Securities Act is applicable) to become effective within
one hundred eighty (180) days following the effective date of any registration
required pursuant to this Section 2 or such lesser period as may be consented to
by the managing underwriter.

     3. "Market Stand-Off" Agreement. Notwithstanding the rights granted
pursuant to Section 2(a), each Investor hereby agrees that, during the period of
duration (not to exceed 180 days) specified by the Company and an underwriter of
Common Stock or other securities of the Company, following the effective date of
a registration statement of the Company filed under the Securities Act, it will
not, to the extent requested by the Company and such underwriter, directly or
indirectly sell, offer to sell, contract to sell (including, without limitation,
any short sale), grant any option to purchase or otherwise transfer or dispose
of any securities of the Company held by it at any time during such period
except shares of Common Stock included in such registration; provided, however,
that:

         (a) such agreement will be applicable only to the first such
registration statement of the Company which covers Common Stock (or other
securities) to be sold on its behalf to the public in an underwritten offering;
and

         (b) all officers and directors of the Company and all other persons
with registration rights (whether or not pursuant to this Agreement) enter into
similar agreements.

     In order to enforce the foregoing covenant, the Company may impose
stop-transfer instructions with respect to the Registrable Securities of each
Investor (and the shares or securities of every other person subject to the
foregoing restriction) until the end of such 180-day period.

     4. Piggyback Registration. If the Company at any time proposes to register
any of its Common Stock under the Securities Act for sale to the public
(including pursuant to a demand under Section 2 hereof as provided therein and
except with respect to registration statements on Forms S-4, S-8 or another form
not available for registering the Registrable Securities for sale to the
public), each such time it will give written notice at the applicable address of
record to each holder of Registrable Securities of its intention to do so. Upon
the written request of any of such holders of the Registrable Securities, given
within thirty (30) days after receipt by such Person of such notice, the Company
will, subject to the limits contained in this Section 4, use its reasonable best
efforts to cause all such Registrable Securities of said requesting holders to
be registered under the Securities Act and qualified for sale under any state
blue sky law, all to the extent required to permit such sale or other
disposition of said Registrable Securities; provided, however, that if the
Company is advised in writing in good faith by any managing underwriter of the
Company's securities being offered in a public offering pursuant to such
registration statement that the amount to be sold by persons other than the
Company (collectively, "Selling Stockholders") is greater than the amount which
can be offered without adversely affecting the offering, the Company may reduce
the amount offered for the accounts of Selling Stockholders (including such
holders of shares of Registrable Securities) to a number deemed satisfactory by
such managing underwriter; and provided further, that the shares to be excluded
shall be determined in the following sequence (except with respect to a demand
under Section 2 hereof): (i) first, securities held by any Persons not having
any such contractual, incidental registration rights; (ii) second, securities
held by any Persons having contractual, incidental registration

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rights pursuant to an agreement which is not this Agreement; (iii) third,
securities held by the Founders (as defined in the Purchase Agreement); and (iv)
fourth, all Registrable Securities in each case as determined on a pro rata
basis in accordance with their holdings. Notwithstanding the foregoing, except
with respect to the Company's first registration of Common Stock pursuant to the
Securities Act, in no event shall the number of Registrable Securities included
in a registration pursuant to this section be reduced to less than twenty
percent (20%) of all shares to be registered.

     5. Registration Procedures. If and whenever the Company is required by the
provisions of this Agreement to use its reasonable best efforts to effect the
registration of any of its securities under the Securities Act, the Company
will, as expeditiously as possible:

         (a) use its best efforts diligently to prepare and file with the
Commission a registration statement on the appropriate form under the Securities
Act with respect to such securities, which form shall comply as to form in all
material respects with the requirements of the applicable form and include all
financial statements required by the Commission to be filed therewith, and use
its reasonable best efforts to cause such registration statement to become and
remain effective until completion of the proposed offering (but not for more
than one hundred eighty (180) days);

         (b) prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in connection
therewith as may be necessary to keep such registration statement effective
until the completion of the offering (but not for more than one hundred eighty
(180) days) and to comply with the provisions of the Securities Act with respect
to the sale or other disposition of all securities covered by such registration
statement whenever the seller or sellers of such securities shall desire to sell
or otherwise dispose of the same, but only to the extent provided in this
Agreement;

         (c) furnish to each selling holder of Registrable Securities and the
underwriters, if any, such number of copies of such registration statement, any
amendments thereto, any documents incorporated by reference therein, the
prospectus, including a preliminary prospectus, in conformity with the
requirements of the Securities Act, and such other documents as such selling
holder may reasonably request in order to facilitate the public sale or other
disposition of the securities owned by such selling holder;

         (d) use its best efforts to register or qualify the securities covered
by such registration statement under and to the extent required by such other
securities or state blue sky laws of such jurisdictions as each selling holder
of Registrable Securities shall reasonably request, and do any and all other
acts and things which may be necessary under such securities or blue sky laws to
enable such selling holder to consummate the public sale or other disposition in
such jurisdictions of the securities owned by such selling holder, except that
the Company shall not for any such purpose be required to qualify to do business
as a foreign corporation in any jurisdiction wherein it is not so qualified;

         (e) within a reasonable time before each filing of the registration
statement or prospectus or amendments or supplements thereto with the
Commission, furnish to counsel selected by the holders of a Majority Interest
copies of such documents proposed to be filed,

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which documents shall be subject to the reasonable approval of such counsel,
which approval shall not be unreasonably withheld;

         (f) promptly notify each selling holder of Registrable Securities, such
selling holders' counsel and any underwriter and (if requested by any such
Person) confirm such notice in writing, of the happening of any event which
makes any statement made in the registration statement or related prospectus
untrue or which requires the making of any changes in such registration
statement or prospectus so that they will not contain any untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein in the light of the circumstances
under which they were made not misleading; and, as promptly as practicable
thereafter, prepare and file with the Commission and furnish a supplement or
amendment to such prospectus so that, as thereafter deliverable to the
purchasers of such Registrable Securities, such prospectus will not contain any
untrue statement of a material fact or omit to state a material fact necessary
to make the statements therein, in the light of the circumstances under which
they were made, not misleading;

         (g) use its reasonable best efforts to prevent the issuance of any
order suspending the effectiveness of a registration statement, and if one is
issued use its reasonable best efforts to obtain the withdrawal of any order
suspending the effectiveness of a registration statement at the earliest
possible moment;

         (h) if requested by the managing underwriter or underwriters (if any),
any selling holder of Registrable Securities, or such selling holder's counsel,
promptly incorporate in a prospectus supplement or post-effective amendment such
information as such Person requests to be included therein with respect to the
selling holder or the securities being sold, including, without limitation, with
respect to the securities being sold by such selling holder to such underwriter
or underwriters, the purchase price being paid therefor by such underwriter or
underwriters and with respect to any other terms of an underwritten offering of
the securities to be sold in such offering, and promptly make all required
filings of such prospectus supplement or post-effective amendment;

         (i) make available to each selling holder of Registrable Securities,
any underwriter participating in any disposition pursuant to a registration
statement, and any attorney, accountant or other agent or representative
retained by any such selling holder or underwriter (collectively, the
"Inspectors"), all financial and other records, pertinent corporate documents
and properties of the Company (collectively, the "Records"), as shall be
reasonably necessary to enable them to exercise their due diligence
responsibility, and cause the Company's officers, directors and employees to
supply all information requested by any such Inspector in connection with such
registration statement subject, in each case, to such confidentiality agreements
as the Company shall reasonably request;

         (j) enter into any reasonable underwriting agreement required by the
proposed underwriter(s) for the selling holders of Registrable Securities, if
any, and use its reasonable best efforts to facilitate the public offering of
the securities;

         (k) request that each prospective selling holder be furnished a signed
counterpart, addressed to the prospective selling holder, of , if and to the
extent permitted by

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applicable professional standards, a "comfort" letter signed by the independent
public accountants who have certified the Company's financial statements
included in the registration statement, covering substantially the same matters
with respect to the registration statement (and the prospectus included therein)
and with respect to events subsequent to the date of the financial statements,
as are customarily covered (at the time of such registration) in accountants'
letters delivered to the underwriters in underwritten public offerings of
securities;

         (l) use its reasonable best efforts to cause the securities covered by
such registration statement to be listed on the securities exchange or quoted on
the quotation system on which the Common Stock is then listed or quoted (or, if
the Common Stock is not yet listed or quoted, then on such exchange or quotation
system as the selling holders of Registrable Securities and the Company shall
determine);

         (m) otherwise use its reasonable best efforts to comply with all
applicable rules and regulations of the Commission and make generally available
to its security holders, in each case as soon as reasonably practicable, but not
later than 90 days after the close of the period covered thereby, an earnings
statement of the Company which will satisfy the provisions of Section 11(a) of
the Securities Act and Rule 158 thereunder (or any comparable successor
provisions); and

         (n) otherwise cooperate with the underwriter(s), the Commission and
other regulatory agencies and take all reasonable actions and execute and
deliver or cause to be executed and delivered all documents reasonably necessary
to effect the registration of any securities under this Agreement.

     6. Expenses. All reasonable expenses incurred by the Company and the
Investors in effecting the registrations provided for in Sections 2, 3 and 4,
including, without limitation, all registration and filing fees, printing
expenses, fees and disbursements of counsel for the Company and one counsel for
the selling stockholders as a group (selected by a majority in interest of the
holders of Registrable Securities who participate in the registration),
underwriting expenses (other than fees, commissions or discounts), expenses of
any audits incident to or required by any such registration and expenses of
complying with the securities or blue sky laws of any jurisdictions pursuant to
Section 5(d) hereof (all of such expenses referred to as "Registration
Expenses"), shall be paid by the Company.

     7. Indemnification.

         (a) To the maximum extent permitted by law, the Company shall indemnify
and hold harmless the selling holder of Registrable Securities, each underwriter
(as defined in the Securities Act), and each other Person, if any, who controls
(within the meaning of the Securities Act) such selling holder or underwriter
(individually and collectively, the "Indemnified Person") against any losses,
claims, damages or liabilities (collectively, "liability"), joint or several, to
which such Indemnified Person may become subject under the Securities Act or any
other statute or at common law, insofar as such liability (or action in respect
thereof) arises out of or is based upon (i) any untrue statement or alleged
untrue statement of any material fact contained, on the effective date thereof,
in any registration statement under which such securities were registered under
the Securities Act, any preliminary prospectus or final prospectus contained
therein, or any

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amendment or supplement thereto, or (ii) any omission or alleged omission to
state therein a material fact required to be stated therein or necessary to make
the statements therein not misleading. Except as otherwise provided in Section
7(e), the Company shall reimburse each such selling holder of Registrable
Securities in connection with investigating or defending any such liability as
reasonable expenses in connection with the same are incurred; provided, however,
that the Company shall not be liable to any such selling holder of Registrable
Securities in any such case to the extent that any such liability arises out of
or is based upon any untrue statement or alleged untrue statement or omission or
alleged omission made in such registration statement, preliminary or final
prospectus, or amendment or supplement thereto in reliance upon and in
conformity with information furnished in writing to the Company by such selling
holder of Registrable Securities specifically for use therein; and provided
further, that the Company shall not be required to indemnify any Indemnified
Person against any liability arising from any untrue or misleading statement or
omission contained in any preliminary prospectus if such deficiency is corrected
in the final prospectus or for any liability which arises out of the failure of
any Indemnified Person to deliver a prospectus as required by the Securities
Act.

         (b) Each selling holder of any securities included in such registration
being effected shall indemnify and hold harmless each other selling holder of
any securities, the Company, its directors and officers, each underwriter and
each other Person, if any, who controls (within the meaning of the Securities
Act) the Company or such underwriter (individually and collectively also the
"Indemnified Person"), against any liability, joint or several, to which any
such Indemnified Person may become subject under the Securities Act or any other
statute or at common law, insofar as such liability (or actions in respect
thereof) arises out of or is based upon (i) any untrue statement or alleged
untrue statement of any material fact contained, on the effective date thereof,
in any registration statement under which securities were registered under the
Securities Act at the request of such selling holder, any preliminary prospectus
or final prospectus contained therein, or any amendment or supplement thereto,
or (ii) any omission or alleged omission by such selling holder to state therein
a material fact required to be stated therein or necessary to make the
statements therein not misleading, in the case of (i) and (ii) to the extent,
but only to the extent, that such untrue statement or alleged untrue statement
or omission or alleged omission was made in such registration statement,
preliminary or final prospectus, amendment or supplement thereto in reliance
upon and in conformity with information furnished in writing to the Company by
such selling holder specifically for use therein. Such selling holder shall
reimburse any Indemnified Person for any legal fees incurred in investigating or
defending any such liability; provided, however, that such selling holder's
obligations hereunder shall be limited to an amount equal to the proceeds to
such selling holder of the securities sold in any such registration; and
provided further, that no selling holder shall be required to indemnify any
Person against any liability arising from any untrue or misleading statement or
omission contained in any preliminary prospectus if such deficiency is corrected
in the final prospectus or for any liability which arises out of the failure of
any Person to deliver a prospectus as required by the Securities Act.

         (c) Indemnification similar to that specified in Sections 7(a) and (b)
shall be given by the Company and each selling holder (with such modifications
as may be appropriate) with respect to any required registration or other
qualification of their securities under any federal or state law or regulation
of governmental authority other than the Securities Act.

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         (d) Promptly after receipt by an Indemnified Person under this Section
7 of notice of the commencement of any action (including any governmental
action), such Indemnified Person will, if a claim in respect thereof is to be
made against any indemnifying party under this Section 7, deliver to the
indemnifying party a written notice of the commencement thereof and the
indemnifying party will have the right to participate in, and, to the extent the
indemnifying party so desires, jointly with any other indemnifying party
similarly noticed, to assume the defense thereof with qualified counsel;
provided, however, that an Indemnified Person (together with all other
Indemnified Persons which may be represented without conflict by one counsel)
will have the right to retain one separate counsel, with the reasonable fees and
expenses to be paid by the indemnifying party, if representation of such
Indemnified Person by the counsel retained by the indemnifying party is
inappropriate due to actual or potential differing interests between such
Indemnified Person and any other party represented by such counsel in such
proceeding. The failure to deliver written notice to the indemnifying party
within a reasonable time of the commencement of any such action, if prejudicial
to its ability to defend such action, will relieve such indemnifying party of
any liability to the Indemnified Person under this Section 7, but the omission
so to deliver written notice to the indemnifying party will not relieve it of
any liability that it may have to any Indemnified Person otherwise than under
this Section 7.

         (e) If the indemnification provided for in this Section 7 for any
reason is held by a court of competent jurisdiction to be unavailable to an
Indemnified Person in respect of any losses, claims, damages, expenses or
liabilities referred to therein, then each indemnifying party under this Section
7, in lieu of indemnifying such Indemnified Person thereunder, shall contribute
to the amount paid or payable by such Indemnified Person as a result of such
losses, claims, damages, expenses or liabilities (i) in such proportion as is
appropriate to reflect the relative benefits received by the Company, the
selling holders and the underwriters from the offering of the Registrable
Securities or (ii) if the allocation provided by clause (i) above is not
permitted by applicable law, in such proportion as is appropriate to reflect not
only the relative benefits referred to in clause (i) above but also the relative
fault of the Company, the other selling holders and the underwriters in
connection with the statements or omissions which resulted in such losses,
claims, damages, expenses or liabilities, as well as any other relevant
equitable considerations. The relative benefits received by the Company, the
selling holders and the underwriters shall be deemed to be in the same
respective proportions that the net proceeds from the offering (before deducting
expenses) received by the Company and the selling holders and the underwriting
discount received by the underwriters, in each case as set forth in the table on
the cover page of the applicable prospectus, bear to the aggregate public
offering price of the Registrable Securities. The relative fault of the Company,
the selling holders and the underwriters shall be determined by reference to,
among other things, whether the untrue or alleged untrue statement of a material
fact or the omission or alleged omission to state a material fact relates to
information supplied by the Company, the selling holders or the underwriters and
the parties' relative intent, knowledge, access to information and opportunity
to correct or prevent such statement or omission.

         (f) The Company, the selling holders and the underwriters agree that it
would not be just and equitable if contribution pursuant to this Section 7 were
determined by pro rata or per capita allocation or by any other method of
allocation which does not take account of the equitable considerations referred
to in the immediately preceding paragraph. In no event, however, shall a selling
holder be required to contribute any amount under this Section 7(f) in

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excess of the lesser of (i) that proportion of the total of such losses, claims,
damages or liabilities indemnified against equal to the proportion of the total
Registrable Securities sold under such registration statement which are being
sold by such selling holder or (ii) the proceeds received by such selling holder
from its sale of Registrable Securities under such registration statement. No
person found guilty of fraudulent misrepresentation (within the meaning of
Section 11(f) of the Securities Act) shall be entitled to contribution from any
person who was not found guilty of such fraudulent misrepresentation.

         (g) Notwithstanding the foregoing, to the extent that the provisions on
indemnification and contribution contained in the underwriting agreement entered
into in connection with an underwritten public offering are in conflict with the
foregoing provisions, the provisions in the underwriting agreement shall
control.

     8. Compliance with Rule 144.

         (a) In the event that the Company (i) registers a class of securities
under Section 12 of the Exchange Act or (ii) shall commence to file reports
under Section 13 or 15(d) of the Exchange Act, the Company will use its best
efforts thereafter to file with the Commission such information as is required
under the Exchange Act for so long as there are holders of Registrable
Securities; and in such event, the Company shall use its best efforts to take
all action as may be required as a condition to the availability of Rule 144.
The Company shall furnish to any holder of Registrable Securities upon
reasonable request a written statement executed by the Company as to the steps
it has taken to comply with the current public information requirement of Rule
144. After the occurrence of the first underwritten public offering of Common
Stock pursuant to an offering registered under the Securities Act on Form S-1 or
Form SB-2 (or any comparable successor forms), subject to the limitations on
transfers imposed by this Agreement, the Company shall use its reasonable best
efforts to facilitate and expedite transfers of Registrable Securities pursuant
to Rule 144, which efforts shall include timely notice to its transfer agent to
expedite such transfers of Registrable Securities.

         (b) Except with respect to a demand registration pursuant to Section 2,
prior to the Company's registration of any Registrable Securities hereunder on
behalf of an Investor, such Investor shall (i) use its reasonable best efforts
to sell the maximum number of Registrable Securities that such Investor is able
to sell pursuant to Rule 144 and (ii) exercise the registration rights hereunder
only in the case that such Investor determines in good faith that such rights
are necessary to sell such Registrable Securities in a timely manner.

     9. Amendments. The provisions of this Agreement may be amended, and the
Company may take any action herein prohibited or omit to perform any act herein
required to be performed by it, only with the written consent of the Company and
a Majority Interest of the Investors.

     10. Transferability of Registration Rights. The registration rights set
forth in this Agreement are transferable to each valid and proper transferee of
at least Two Million (2,000,000) shares of Registrable Securities. Each such
transferee of Registrable Securities must consent in writing to be bound by the
terms and conditions of this Agreement in order to acquire the rights granted
pursuant to this Agreement.

                                       10
<PAGE>

     11. Rights Which May Be Granted to Subsequent Investors. Other than
transferees of Registrable Securities under Section 10 hereof, the Company shall
not, without the prior written consent of a Majority Interest of the Investors,
(a) allow purchasers of the Company's securities to become a party to this
Agreement or (b) grant any other registration rights to any third parties other
than subordinate piggyback registration rights.

     12. Damages. The Company recognizes and agrees that each holder of
Registrable Securities will not have an adequate remedy if the Company fails to
comply with the terms and provisions of this Agreement and that damages will not
be readily ascertainable, and the Company expressly agrees that, in the event of
such failure, it shall not oppose an application by any holder of Registrable
Securities or any other Person entitled to the benefits of this Agreement
requiring specific performance of any and all provisions hereof or enjoining the
Company from continuing to commit any such breach of this Agreement.

     13. Miscellaneous.

         (a) All notices, requests, demands and other communications provided
for hereunder shall be in writing and mailed (by first class registered or
certified mail, postage prepaid), telegraphed, sent by express overnight courier
service or electronic facsimile transmission (with a copy by mail), or delivered
to the applicable party at the addresses indicated below:

       If to the Company:          WebSideStory, Inc.
                                   6450 Lusk Boulevard, Suite E-205
                                   San Diego, CA  92121
                                   Facsimile: (619) 546-0480
                                   Attn:  President and Chief Executive Officer

       If to the Investors:        TA Associates, Inc.
                                   70 Willow Road, Suite 100
                                   Menlo Park, California 94025
                                   Facsimile: (650) 326-4933
                                   Attn: Mr. Benjamin H. Ball

                                   Summit Partners
                                   499 Hamilton Avenue, Suite 200
                                   Palo Alto, CA  94301
                                   Facsimile: (650) 321-1188
                                   Attn: Mr. Walter G. Kortschak

       If to any other holder of Registrable Securities:

               At such Person's address for notice as set forth in the books and
               records of the Company.

or, as to each of the foregoing, at such other address as shall be designated by
such Person in a written notice to other parties complying as to delivery with
the terms of this subsection (a). All

                                       11
<PAGE>

such notices, requests, demands and other communications shall, when mailed,
telegraphed or sent, respectively, be effective (i) two days after being
deposited in the mails or (ii) one day after being delivered to the telegraph
company, deposited with the express overnight courier service or sent by
electronic facsimile transmission, respectively, addressed as aforesaid.

         (b) This Agreement shall be governed by and construed in accordance
with the laws of the State of California, without giving effect to conflict of
laws principles thereof.

         (c) This Agreement may be executed in two or more counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

         (d) If any provision of this Agreement shall be held to be illegal,
invalid or unenforceable, such illegality, invalidity or unenforceability shall
attach only to such provision and shall not in any manner affect or render
illegal, invalid or unenforceable any other provision of this Agreement, and
this Agreement shall be carried out as if any such illegal, invalid or
unenforceable provision were not contained herein.

     14. Dispute Resolution. Except as provided below, any dispute arising out
of or relating to this Agreement or the breach, termination or validity hereof
shall be finally settled by binding arbitration conducted expeditiously by one
arbitrator in accordance with the J.A.M.S./Endispute Streamlined Arbitration
Rules and Procedures (the "J.A.M.S. Rules"). The arbitration shall be governed
by the United States Arbitration Act, 9 U.S.C. Sections 1-16, and judgment upon
the award rendered by the arbitrator may be entered by any court having
jurisdiction thereof. The place of arbitration shall be San Diego, California.

     Such proceedings shall be administered by the arbitrator in accordance with
the J.A.M.S. Rules as he/she deems appropriate, however, such proceedings shall
be conducted in accordance with the following agreed upon procedures:

         (a) mandatory exchange of all relevant documents, to be accomplished
within forty-five (45) days of the initiation of the procedure (documents not so
exchanged will be excluded from the evidence considered at the hearing absent a
showing of good cause);

         (b) no other discovery;

         (c) hearings before the arbitrator which shall consist of a summary
presentation by each side of not more than three (3) hours; such hearings to
take place on one or two days at a maximum; and

         (d) decision to be rendered not more than ten (10) days following such
hearings.

     Notwithstanding anything to the contrary contained herein, the provisions
of this Section 14 shall not apply with regard to any equitable remedies to
which any party may be entitled hereunder.

                                       12
<PAGE>

     Each of the parties hereto (a) hereby irrevocably submits to the personal
jurisdiction of any court of competent jurisdiction in the United States for the
purpose of enforcing the award or decision in any such proceeding, (b) hereby
waives, and agrees not to assert, by way of motion, as a defense, or otherwise,
in any such suit, action or proceeding, any claim that it is not subject
personally to the jurisdiction of the above-named courts, that its property is
exempt or immune from attachment or execution (except as protected by applicable
law), that the suit, action or proceeding is brought in an inconvenient forum,
that the venue of the suit, action or proceeding is improper or that this
Agreement or the subject matter hereof may not be enforced in or by such court,
and hereby waives and agrees not to seek any review by any court of any other
jurisdiction which may be called upon to grant an enforcement of the judgment of
any such court. Each of the parties hereto hereby consents to service of process
by registered mail at the address to which notices are to be given. Each of the
parties hereto agrees that its or his submission to jurisdiction and its or his
consent to service of process by mail is made for the express benefit of the
other parties hereto. Final judgment against any party hereto in any such
action, suit or proceeding may be enforced in other jurisdictions by suit,
action or proceeding on the judgment, or in any other manner provided by or
pursuant to the laws of such other jurisdiction.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                       13
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Registration Rights
Agreement to be duly executed as of the date first set forth above.

                              THE COMPANY:

                              WEBSIDESTORY, INC.

                              By:    /s/ Blaise Barrelet
                                    ____________________________________
                                    Name:  Blaise Barrelet
                                    Title: President and Chief Executive Officer

                                       14
<PAGE>

                                INVESTORS:

                                SUMMIT VENTURES V, L.P.
                                By: Summit Partners V, L.P., its General Partner
                                By: Summit Partners, LLC, its General Partner

                                /s/ Walter G. Kortschak
                                ----------------------------------
                                Walter G. Kortschak
                                Member

                                SUMMIT V COMPANION FUND, L.P.
                                By: Summit Partners V, L.P., its General Partner
                                By: Summit Partners, LLC, its General Partner

                                /s/ Walter G. Kortschak
                                ----------------------------------
                                Walter G. Kortschak
                                Member

                                SUMMIT V ADVISORS FUND, L.P.
                                By: Summit Partners, LLC, its General Partner

                                /s/ Walter G. Kortschak
                                ----------------------------------
                                Walter G. Kortschak
                                Member

                                SUMMIT V ADVISORS FUND (QP), L.P.
                                By: Summit Partners, LLC, its General Partner

                                /s/ Walter G. Kortschak
                                ----------------------------------
                                Walter G. Kortschak
                                Member

                                       15
<PAGE>

                                SUMMIT INVESTORS III, L.P.

                                /s/ Walter G. Kortschak
                                ----------------------------------
                                Walter G. Kortschak
                                General Partner

                                TA/ADVENT VIII L.P.
                                By:  TA Associates VIII LLC, its General Partner
                                By:  TA Associates, Inc., its Manager

                                /s/ Jeffrey T. Chambers
                                ----------------------------------
                                Jeffrey T. Chambers
                                Managing Director

                                ADVENT ATLANTIC AND PACIFIC III L.P.
                                By:  TA Associates AAP III Partners, its
                                     General Partner
                                By:  TA Associates, Inc., its General Partner

                                /s/ Jeffrey T. Chambers
                                ----------------------------------
                                Jeffrey T. Chambers
                                Managing Director

                                TA INVESTORS LLC
                                By:   TA Associates, Inc., its Manager

                                /s/ Jeffrey T. Chambers
                                ----------------------------------
                                Jeffrey T. Chambers
                                Managing Director

                                       16
<PAGE>

                                TA EXECUTIVES FUND LLC
                                By:   TA Associates, Inc., its Manager

                                /s/ Jeffrey T. Chambers
                                ----------------------------------
                                Jeffrey T. Chambers
                                Managing Director

                [SIGNATURE PAGE TO REGISTRATION RIGHTS AGREEMENT]

                                       17
<PAGE>

                               WEBSIDESTORY, INC.

                   AMENDMENT TO REGISTRATION RIGHTS AGREEMENT

      This Amendment (this "Amendment") to that Registration Rights Agreement
dated June 18, 1999 (the "Original Agreement"), is entered into as of this
December 12, 2000 by and among WebSideStory, Inc., a Delaware corporation (the
"Company"), the Investors (as defined in the Original Agreement, herein
collectively referred to as the "Existing Investors") and the investors (the
"Purchase Investors") named in the Schedule of Investors attached to the Series
B Convertible Preferred Stock Purchase Agreement of even date herewith (the
"Purchase Agreement"). Capitalized terms not otherwise defined in this Amendment
shall have the meanings ascribed to them by the Original Agreement or the
Purchase Agreement.

                                    RECITALS

A.    The Company now desires to sell and issue, upon the effectiveness of the
      Second Amended and Restated Certificate of Incorporation of the Company,
      up to an aggregate of 11,590,535 shares of Series B Convertible Redeemable
      Participating Preferred Stock (the "Preferred Shares") pursuant to Section
      1 of the Purchase Agreement and to provide the Purchase Investors certain
      registration rights and other rights related to the Shares consistent with
      those previously granted to the Existing Investors under the Original
      Agreement; and

B.    Each of the Existing Investors desires to consent to the addition of the
      Purchase Investors as parties to the Original Agreement.

                                    AGREEMENT

      NOW THEREFORE, in consideration of the mutual promises, covenants and
conditions set forth below, the parties hereby agree and consent to the
amendment of the Original Agreement, effective upon the sale of the Preferred
Shares to the Purchase Investors and the effectiveness of the 8-for-l reverse
stock split of the outstanding shares of Common Stock of the Company, as
follows:

      1. Addition of Purchase Investors to Original Agreement. Effective upon
the sale by the Company of the Preferred Shares to the Purchase Investors, the
parties hereto agree (a) that each of the Purchase Investors is hereby added as
parties to the Original Agreement and included under the definition of
"Investors", and (b) that each of the Purchase Investors for so long as each of
the Purchase Investors holds Registrable Stock is included as an "Investor" for
all relevant purposes under the Original Agreement, as amended hereby, shall be
bound by the terms of the Original Agreement, as amended hereby. Each of the
Purchase Investors represents, warrants, agrees, consents and acknowledges that
(a) he/she/it has received a copy of the Original Agreement, (b) he/she/it has
reviewed and understands the Original Agreement, and (c) by his/hers/its
execution and delivery of a counterpart signature page of this Amendment, agrees
to be bound by the terms, conditions and provisions of the Original Agreement as
modified by this Amendment.

      2. Registrable Securities. The parties hereto agree to include the shares
of Common Stock issued or issuable upon conversion of the Preferred Shares in
the definition of "Registrable Securities" as such term is defined in Section 1
of the Original Agreement, and that the terms and conditions of the Original
Agreement, as amended hereby, shall govern the registration rights with respect
to the Preferred Shares without any amendment or distinctions being made between
the Preferred Shares and the "Registrable Securities" as originally defined in
the Original Agreement.

                                       1

<PAGE>

      3. Governing Law. The parties hereby agree to change the governing law of
the Original Agreement set forth in Section 13(b) of the Original Agreement from
the laws of the State of California to the laws of the State of Delaware
(without giving effect to principles of conflicts of law).

      4. Effectiveness of Amendment. In accordance with Section 9 of the
Original Agreement, this Amendment will not be effective unless the Company and
a Majority in Interest of the Investors consent in writing to this Amendment.

      5. Continued Effect. Except as otherwise expressly provided herein and
amended hereby, the Original Agreement will continue in full force and effect,
in accordance with its terms.

      6. Miscellaneous. This Amendment will be governed in all respects by the
laws of the State of Delaware as such laws are applied to agreements between
Delaware residents entered into and to be performed entirely within Delaware.
This Amendment constitutes the full and entire understanding and agreement among
the parties with regard to the subjects hereof and supersedes all prior written
and oral agreements, representations and commitments, if any, among the parties
with respect to such subjects. This Amendment may be executed in any number of
counterparts, each of which will be an original, but all of which together will
constitute one instrument. Any provision of this Amendment may be waived or
modified only in accordance with the provisions set forth in the Original
Agreement.

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK.]

                                       2

<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to the
Registration Rights Agreement to be duly executed and delivered by their proper
and duly authorized representatives as of the day and year first above written.

                                        "COMPANY":

                                        WEBSIDESTORY, INC.

                                        By: /s/ John J. Hentrich
                                           -------------------------------------
                                           John J. Hentrich
                                           President and Chief Executive Officer

                         [COUNTERPART SIGNATURE PAGE TO
                  AMENDMENT TO REGISTRATION RIGHTS AGREEMENT]

<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to the
Registration Rights Agreement to be duly executed and delivered by their proper
and duly authorized representatives as of the day and year first above written.

                               "EXISTING INVESTORS"

                               TA/ADVENT VIII L.P.
                               By: TA Associates VIII LLC, its General Partner
                               By: TA Associates, Inc., its Manager

                               By:  *
                                  ----------------------------------------------

                               ADVENT ATLANTIC AND PACIFIC III L.P.
                               By: TA Associates AAP III Partners,
                                   its General Partner
                               By: TA Associates, Inc., its General Partner

                               By:  *
                                  ----------------------------------------------

*By: /s/ Kurt R. Jaggers
     ---------------------     TA INVESTORS LLC
     Kurt R. Jaggers           BY: TA Associates Inc., its Manager
     Managing Director

                               By:  *
                                  ----------------------------------------------

                               TA EXECUTIVES FUND LLC
                               By: TA Associates, Inc., its Manager

                               By:  *
                                  ----------------------------------------------

                         [COUNTERPART SIGNATURE PAGE TO
                  AMENDMENT TO REGISTRATION RIGHTS AGREEMENT]

<PAGE>

                               JOINDER AGREEMENT

         The undersigned, having purchased shares of Series B Preferred Stock of
WebSideStory, Inc., a Delaware corporation (the "Company") hereby agree, that
with respect to such Series B Preferred Stock, the undersigned will be bound by
the terms and conditions of, and become a party to the Stock Purchase Agreement
by and among the Company and certain investors dated as of December 13, 2000,
the Registration Rights Agreement by and among the Company and certain investors
dated as of June 18, 1999, and as amended as of December 13, 2000, and the
Stockholders' Agreement by and among the Company, certain common stockholders
and certain investors dated as of June 18, 1999, and as amended as of December
13, 2000 as an "Investor" or "Purchase Investor," respectively, as defined
thereunder, the forms of which are attached hereto, as if the undersigned had
been a party to such agreements with respect to such shares of Series B
Preferred Stock as of the date thereof,

/s/ Keith Fisher
------------------------
Keith Fisher                                           Date: January 19, 2001

Address: 3191 A Street
         San Diego, CA 92102
Fax:     619.234.1797

No. of shares of Series B Stock : 3,152

/s/John T. Hentrich
-----------------------
John T. Hentrich                            Date:_____________________

Address:_____________________
        _____________________
Fax:_________________________

No. of shares of Series B Stock : 57,953
<PAGE>

                               WEBSIDESTORY, INC.

                   AMENDMENT TO REGISTRATION RIGHTS AGREEMENT

      This Amendment (this "Amendment") to that Registration Rights Agreement
dated June 18, 1999, as amended to date (as so amended, the "Original
Agreement"), is entered into as of this March 2, 2001 by and among WebSideStory,
Inc., a Delaware corporation (the "Company"), the investors currently party to
the Original Agreement (herein collectively referred to as the "Existing
Investors") and the investors (the "Purchase Investors") named in the Schedule
of Investors attached to the Series C Convertible Preferred Stock Purchase
Agreement of even date herewith (the "Purchase Agreement"). Capitalized terms
not otherwise defined in this Amendment shall have the meanings ascribed to them
by the Original Agreement or the Purchase Agreement.

                                    RECITALS

A.    The Company now desires to sell and issue, upon the effectiveness of the
      Third Restated Certificate of Incorporation of the Company, up to an
      aggregate of 2,054,794 shares of Series C Convertible Redeemable
      Participating Preferred Stock (the "Preferred Shares") pursuant to Section
      1 of the Purchase Agreement and to provide the Purchase Investors certain
      registration rights and other rights related to the Shares consistent with
      those previously granted to the Existing Investors under the Original
      Agreement; and

B.    Each of the Existing Investors desires to consent to the addition of the
      Purchase Investors as parties to the Original Agreement.

                                    AGREEMENT

      NOW THEREFORE, in consideration of the mutual promises, covenants and
conditions set forth below, the parties hereby agree and consent to the
amendment of the Original Agreement, effective upon the sale of the Preferred
Shares to the Purchase Investors, as follows:

      1. Addition of Purchase Investors to Original Agreement. Effective upon
the sale by the Company of the Preferred Shares to the Purchase Investors, the
parties hereto agree (a) that each of the Purchase Investors is hereby added as
parties to the Original Agreement and included under the definition of
"Investors", and (b) that each of the Purchase Investors for so long as each of
the Purchase Investors holds Registrable Stock is included as an "Investor" for
all relevant purposes under the Original Agreement, as amended hereby, shall be
bound by the terms of the Original Agreement, as amended hereby. Each of the
Purchase Investors represents, warrants, agrees, consents and acknowledges that
(a) he/she/it has received a copy of the Original Agreement, (b) he/she/it has
reviewed and understands the Original Agreement, and (c) by his/hers/its
execution and delivery of a counterpart signature page of this Amendment, agrees
to be bound by the terms, conditions and provisions of the Original Agreement as
modified by this Amendment.

      2. Registrable Securities. The parties hereto agree to include the shares
of Common Stock issued or issuable upon conversion of the Preferred Shares in
the definition of "Registrable Securities" as such term is defined in Section 1
of the Original Agreement, and that the terms and conditions of the Original
Agreement, as amended hereby, shall govern the registration rights with respect
to the Preferred Shares without any amendment or distinctions being made between
the Preferred Shares and the "Registrable Securities" as originally defined in
the Original Agreement.

                                       1

<PAGE>

      3. Effectiveness of Amendment. In accordance with Section 9 of the
Original Agreement, this Amendment will not be effective unless the Company and
a Majority in Interest of the Existing Investors consent in writing to this
Amendment.

      4. 4. Market Standoff. A new subsection 3(b) as provided below is hereby
added to the Original Agreement and the existing subsection 3(b) to the original
Agreement will be renumbered to 3(c). The new subsection 3(b) provides:

                  (b) such agreement will not be applicable to securities
purchased in public market transactions; and

      5. Transferability. Notwithstanding anything to the contrary in the
Original Agreement, Investors may transfer all rights under the Original
Agreement, as may be amended from time to time, to any affiliate, partner,
member, stockholder, or former partner, member or stockholder of an Investor.

      6. Attorneys' Fees. In the event that any dispute among the parties to
this Agreement should result in litigation, the prevailing party in such dispute
shall be entitled to recover from the losing party all fees, costs and expenses
of enforcing any right of such prevailing party under or with respect to this
Agreement, including, without limitation, such reasonable fees and expenses of
attorneys and accountants, which shall include, without limitation, all fees,
costs and expenses of appeal.

      7. Continued Effect. Except as otherwise expressly provided herein and
amended hereby, the Original Agreement will continue in full force and effect,
in accordance with its terms.

      8. Notice or Demand. Any notice or demand which is required or provided to
be given under this Amendment shall be deemed to have been sufficiently given
and received for all purposes when delivered by hand, telecopy, telex or other
method of facsimile, or five (5) days after being sent by certified or
registered mail, postage and charges prepaid, return receipt requested, or two
(2) days after being sent by overnight delivery providing receipt of delivery,
to:

            a. If to the Company, at 10182 Telesis Court, 6th Floor, San Diego,
California 92121 or at such other address designated by the Company to the
Investors and the other parties hereto in writing; and

            b. If to the Purchase Investors, at the mailing addresses as shown
on the Schedule of Investors attached to the Purchase Agreement or at such other
address designated by a Purchase Investor to the Company in writing.

      9. Miscellaneous. This Amendment will be governed in all respects by the
laws of the State of Delaware as such laws are applied to agreements between
Delaware residents entered into and to be performed entirely within Delaware.
This Amendment constitutes the full and entire understanding and agreement among
the parties with regard to the subjects hereof and supersedes all prior written
and oral agreements, representations and commitments, if any, among the parties
with respect to such subjects. This Amendment may be executed in any number of
counterparts, each of which will be an original, but all of which together will
constitute one instrument. Any provision of this Amendment may be waived or
modified only in accordance with the provisions set forth in the Original
Agreement.

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK.]

                                       2

<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to the
Registration Rights Agreement to be duly executed and delivered by their proper
and duly authorized representatives as of the day and year first above written.

                                  "COMPANY":

                                  WEBSIDESTORY, INC.

                                  By: /s/ John J. Hentrich
                                     -------------------------------------------
                                     John J. Hentrich
                                     President and Chief Executive Officer

                         [COUNTERPART SIGNATURE PAGE TO
                  AMENDMENT TO REGISTRATION RIGHTS AGREEMENT]

<PAGE>

                                SUMMIT VENTURES V, L.P.
                                By: Summit Partners V, L.P., its General Partner
                                By: Summit Partners, LLC, its General Partner

                                By:  *
                                   ---------------------------------------------

                                SUMMIT V COMPANION FUND, L.P.
                                By: Summit Partners V, L.P., its General Partner
                                By: Summit Partners, LLC, its General Partner

                                By:  *
By: /s/ Walter G. Kortschak        ---------------------------------------------
   ------------------------
Name: WALTER G. KORTSCHAK
      Managing Partner

                                SUMMIT V ADVISORS FUND, L.P.
                                By: Summit Partners, LLC, its General Partner

                                By:  *
                                   ---------------------------------------------

                                SUMMIT V ADVISORS FUND (QP), L.P.
                                By: Summit Partners, LLC, its General Partner

                                By:  *
                                   ---------------------------------------------

                                SUMMIT INVESTORS III, L.P.

                                By: ____________________________________________
                                Name: __________________________________________
                                Title: _________________________________________

                                COMMON STOCK HOLDERS:
                                By: ____________________________________________
                                Name: __________________________________________

<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to the
Registration Rights Agreement to be duly executed and delivered by their proper
and duly authorized representatives as of the day and year first above written.

                                "EXISTING INVESTORS"

                                TA/ADVENT VIII L.P.
                                By: TA Associates VIII LLC, its General Partner
                                By: TA Associates, Inc., its Manager

                                BY:   *
                                   ---------------------------------------------
                                ADVENT ATLANTIC AND PACIFIC III L.P.
                                By: TA Associates AAP III Partners,
                                    its General Partner
                                By: TA Associates, Inc., its General Partner

                                By:   *
                                   ---------------------------------------------

*By: /s/ Kurt R. Jaggers
    -----------------------
    Kurt R. Jaggers             TA INVESTORS LLC
    Managing Director           By: TA Associates Inc., its Manager

                                By:   *
                                   ---------------------------------------------

                                TA EXECUTIVES FUND LLC
                                By: TA Associates, Inc., its Manager

                                By:   *
                                   ---------------------------------------------

                         [COUNTERPART SIGNATURE PAGE TO
                   AMENDMENT TO REGISTRATION RIGHTS AGREEMENT]

<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to the
Registration Rights Agreement to be duly executed and delivered by their proper
and duly authorized representatives as of the day and year first above written.

WESTCLIFF PARTNERS, L.P.                   WESTCLIFF MASTER FUND, LTD.

By: /s/ Richard Spencer                   By: /s/ Richard Spencer
   -------------------------------------     ----------------------------------
   Richard Spencer, Manager of Westcliff     Richard Spencer, Manager of
   Capital Management, LLC                   Westcliff Capital Management, LLC

Its: General Partner                      Its: Investment Advisor of Westcliff
                                               Master Fund LTD

WESTCLIFF AGGRESSIVE GROWTH               WESTCLIFF LONG/SHORT, L.P.

By: /s/ Richard Spencer                   By: /s/ Richard Spencer
   -------------------------------------     ----------------------------------
  Richard Spencer, Manager of Westcliff      Richard Spencer, Manager of
  Capital Management, LLC                    Westcliff Capital Management, LLC

Its: General Partner                      Its: General Partner

PALM TRUST                                WESTCLIFF SMALL CAP

By: /s/ Richard Spencer                   By: /s/ Richard Spencer
   -------------------------------------     ----------------------------------
  Richard Spencer, Manager of Westcliff      Richard Spencer, Manager of
  Capital Management, LLC                    Westcliff Capital Management, LLC

Its: Investment Advisor of Palm Trust     Its: General Partner

WESTCLIFF PROFIT SHARING PLAN

By: /s/ Richard Spencer
   -------------------------------------
  Richard Spencer, Manager of Westcliff
  Capital Management, LLC

Its: General Partner

                         [COUNTERPART SIGNATURE PAGE TO
                   AMENDMENT TO REGISTRATION RIGHTS AGREEMENT]

<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to the
Registration Rights Agreement to be duly executed and delivered by their proper
and duly authorized representatives as of the day and year first above written.

                                          PENINSULA FUND L.P.

                                          By: /s/ Scott A Redford
                                             -----------------------------------
                                          Name: Scott A Redford
                                          Title: President

                                          COMMON SENSE PARTNERS, L.P.

                                          PENINSULA FOND L.P.
                                          By: __________________________________
                                          Name: ________________________________
                                          Title: _______________________________

                                          By: /s/ Scott A Redford
                                             -----------------------------------
                                          Name: Scott A Redford
                                          Title: President

                         [COUNTERPART SIGNATURE PAGE TO
                   AMENDMENT TO REGISTRATION RIGHT AGREEMENT]<PAGE>
                                                                     EXHIBIT 4.3

THIS WARRANT AND THE SHARES ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, PLEDGED OR
OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT
OR PURSUANT TO RULE 144 OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
CORPORATION AND ITS COUNSEL THAT SUCH REGISTRATION IS NOT REQUIRED.

                            WARRANT TO PURCHASE STOCK

Corporation:               WEBSIDESTORY, INC., a California Corporation
Number of Shares:          80,000
Class of Stock:            Common
Initial Exercise Price:    $2.50 per share
Issue Date:                March 27, 2000
Expiration Date:           March 26, 2005 (Subject to Article 4.1)

        THIS WARRANT CERTIFIES THAT, in consideration of the payment of $1.00
and for other good and valuable consideration, IMPERIAL BANCORP or registered
assignee ("Holder") is entitled to purchase the number of fully paid and
nonassessable shares of the class of securities (the "Shares") of the
corporation (the "Company") at the initial exercise price per Share (the
"Warrant Price") all as set forth above and as adjusted pursuant to Article 2 of
this Warrant, subject to the provisions and upon the terms and conditions set
forth of this Warrant.

ARTICLE 1. EXERCISE

        1.1 Method of Exercise. Holder may exercise this Warrant by delivering
this Warrant and a duly executed Notice of Exercise in substantially the form
attached as Appendix 1 to the principal office of the Company. Unless Holder is
exercising the conversion right set forth in Section 1.2, Holder shall also
deliver to the Company a check for the aggregate Warrant Price for the Shares
being purchased.

        1.2 Conversion Right. In lieu of exercising this Warrant as specified in
Section 1.1, Holder may from time to time convert this Warrant, in whole or in
part, into a number of Shares determined by dividing (a) the aggregate fair
market value of the Shares or other securities otherwise issuable upon exercise
of this Warrant minus the aggregate Warrant Price of such Shares by (b) the fair
market value of one Share. The fair market value of the Shares shall be
determined pursuant to Section 1.3.

        1.3 Fair Market Value. If the Shares are traded regularly in a public
market, the fair market value of the Shares shall be the closing price of the
Shares (or the closing price of the Company's stock into which the Shares are
convertible) reported for the business day immediately before Holder delivers
its Notice of Exercise to the Company. If the Shares are not regularly traded in
a public market, the Board of Directors of the Company shall determine fair
market value in its reasonable good faith judgment. The foregoing
notwithstanding, if Holder advises the Board of Directors in writing that Holder
disagrees with such determination,

                                       1
<PAGE>

then the Company and Holder shall promptly agree upon a reputable investment
banking firm to undertake such valuation. If the valuation of such investment
banking firm is greater than that determined by the Board of Directors, then all
fees and expenses of such investment banking firm shall be paid by the Company.
In all other circumstances, such fees and expenses shall be paid by Holder.

        1.4 Delivery of Certificate and New Warrant. Promptly after Holder
exercises or converts this Warrant, the Company shall deliver to Holder
certificates for the Shares acquired and, if this Warrant has not been fully
exercised or converted and has not expired, a new Warrant representing the
Shares not so acquired.

        1.5 Replacement of Warrants. On receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of loss, theft or destruction, on delivery of an
indemnity agreement reasonably satisfactory in form and amount to the Company
or, in the case of mutilation, on surrender and cancellation of this Warrant,
the Company at its expense shall execute and deliver, in lieu of this Warrant, a
new warrant of like tenor.

        1.6 Repurchase on Sale, Merger, or Consolidation of the Company.

               1.6.1. Acquisition. For the purpose of this Warrant,
"Acquisition" means any sale, license, or other disposition of all or
substantially all of the assets (including intellectual property) of the
Company, or any reorganization, consolidation, or merger of the Company where
the holders of the Company's securities before the transaction beneficially own
less than 50% of the outstanding voting securities of the surviving entity after
the transaction.

               1.6.2. Assumption of Warrant. If upon the closing of any
Acquisition the successor entity assumes the obligations of this Warrant, then
this Warrant shall be exercisable for the same securities, cash, and property as
would be payable for the Shares issuable upon exercise of the unexercised
portion of this Warrant as if such Shares were outstanding on the record date
for the Acquisition and subsequent closing. The Warrant Price shall be adjusted
accordingly. The Company shall use reasonable efforts to cause the surviving
corporation to assume the obligations of this Warrant.

               1.6.3. Nonassumption. If upon the closing of any Acquisition the
successor entity does not assume the obligations of this Warrant and Holder has
not otherwise exercised this Warrant in full, then the unexercised portion of
this Warrant shall be deemed to have been automatically converted pursuant to
Section 1.2 and thereafter Holder shall participate in the Acquisition on the
same terms as other holders of the same class of securities of the Company.

ARTICLE 2. ADJUSTMENTS TO THE SHARES.

                                       2
<PAGE>

        2.1 Stock Dividends, Splits, Etc. If the Company declares or pays a
dividend on its common stock payable in common stock, or other securities,
subdivides the outstanding common stock into a greater amount of common stock,
then upon exercise of this Warrant, for each Share acquired, Holder shall
receive, without cost to Holder, the total number and kind of securities to
which Holder would have been entitled had Holder owned the Shares of record as
of the date the dividend or subdivision occurred.

        2.2 Reclassification, Exchange or Substitution. Upon any
reclassification, exchange, substitution, combination, or other event that
results in a change of the number and/or class of the securities issuable upon
exercise or conversion of this Warrant, Holder shall be entitled to receive,
upon exercise or conversion of this Warrant, the number and kind of securities
and property that Holder would have received for the Shares if this Warrant had
been exercised immediately before such reclassification, exchange, substitution,
or other event. Such an event shall include any automatic conversion of the
outstanding or issuable securities of the Company of the same class or series as
the Shares to common stock pursuant to the terms of the Company's Articles of
Incorporation upon the closing of a registered public offering of the Company's
common stock. The Company or its successor shall promptly issue to Holder a new
Warrant for such new securities or other property. The new Warrant shall provide
for adjustments which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Article 2 including, without limitation,
adjustments to the Warrant Price and to the number of securities or property
issuable upon exercise of the new Warrant. The provisions of this Section 2.2
shall similarly apply to successive reclassifications, exchanges, substitutions,
or other events.

        2.3 Adjustments for Combinations, Etc. If the outstanding Shares are
combined or consolidated, by reclassification or otherwise, into a lesser number
of shares, the Warrant Price shall be proportionately increased, and the number
of shares to which Holder is entitled to receive upon exercise or conversion of
this Warrant shall be adjusted accordingly.

        2.4 Adjustments for Diluting Issuances. The Warrant Price and the number
of Shares issuable upon exercise of this Warrant shall be subject to adjustment,
from time to time, in the manner set forth on Exhibit A, if attached, in the
event of Diluting Issuances (as defined on Exhibit A).

        2.5 No Impairment. The Company shall not, by amendment of its Articles
of Incorporation or through a reorganization, transfer of assets, consolidation,
merger, dissolution, issue, or sale of securities or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms to be
observed or performed under this Warrant by the Company, but shall at all times
in good faith assist in carrying out all the provisions of this Article 2 and in
taking all such action as may be necessary or appropriate to protect Holder's
rights under this Article against impairment. If the Company takes any action
affecting the Shares or its common stock other than as described above that
adversely affects Holder's rights under this Warrant, the Warrant Price shall be
adjusted downward and the number of Shares issuable upon exercise of this
Warrant shall be adjusted upward in such a manner that the aggregate Warrant
Price of this Warrant is unchanged.

                                       3
<PAGE>

        2.6 Certificate as to Adjustments. Upon each adjustment of the Warrant
Price, the Company at its expense shall promptly compute such adjustment, and
furnish Holder with a certificate of its Chief Financial Officer setting forth
such adjustment and the facts upon which such adjustment is based. The Company
shall, upon written request, furnish Holder a certificate setting forth the
Warrant Price in effect upon the date thereof and the series of adjustments
leading to such Warrant Price.

ARTICLE 3. REPRESENTATIONS AND COVENANTS OF THE COMPANY.

        3.1 Representations and Warranties. The Company hereby represents and
warrants to the Holder as follows:

               (a) The initial Warrant Price referenced on the first page of
this Warrant is not greater than the fair market value of the Shares as of the
date of this Warrant.

               (b) All Shares which may be issued upon the exercise of the
purchase right represented by this Warrant, and all securities, if any, issuable
upon conversion of the Shares, shall, upon issuance, be duly authorized, validly
issued, fully paid and nonassessable, and free of any liens and encumbrances
except for restrictions on transfer provided for herein or under applicable
federal and state securities laws.

        3.2 Notice of Certain Events. If the Company proposes at any time (a) to
declare any dividend or distribution upon its common stock, whether in cash,
property, stock, or other securities and whether or not a regular cash dividend;
(b) to offer for subscription pro rata to the holders of any class or series of
its stock any additional shares of stock of any class or series or other rights;
(c) to effect any reclassification or recapitalization of common stock; (d) to
merge or consolidate with or into any other corporation, or sell, lease,
license, or convey all or substantially all of its assets, or to liquidate,
dissolve or wind up; or (e) offer holders of registration rights the opportunity
to participate in an underwritten public offering of the company's securities
for cash, then, in connection with each such event, the Company shall give
Holder (1) at least 20 days prior written notice of the date on which a record
will be taken for such dividend, distribution, or subscription rights (and
specifying the date on which the holders of common stock will be entitled
thereto) or for determining rights to vote, if any, in respect of the matters
referred to in (c) and (d) above; (2) in the case of the matters referred to in
(c) and (d) above at least 20 days prior written notice of the date when the
same will take place (and specifying the date on which the holders of common
stock will be entitled to exchange their common stock for securities or other
property deliverable upon the occurrence of such event); and (3) in the case of
the matter referred to in (e) above, the same notice as is given to the holders
of such registration rights.

        3.3 Information Rights. So long as the Holder holds this Warrant and/or
any of the Shares, the Company shall deliver to the Holder (a) promptly after
mailing, copies of all communiques to the shareholders of the Company, (b)
within ninety (90) days after the end of each fiscal year of the Company, the
annual audited financial statements of the Company certified by independent
public accountants of recognized standing and (c) within forty-five (45)

                                       4
<PAGE>

days after the end of each of the first three quarters of each fiscal year, the
Company's quarterly, unaudited financial statements.

        3.4 Registration Under Securities Act of 1933, as amended. The Company
agrees that the Shares shall be subject to the registration rights set forth on
Exhibit B.

ARTICLE 4. MISCELLANEOUS.

        4.1 Term: Notice of Expiration. This Warrant is exercisable, in whole or
in part, at any time and from time to time on or before the Expiration Date set
forth above. The Company shall give Holder written notice of Holder's right to
exercise this Warrant in the form attached as Appendix 2 not more than 90 days
and not less than 30 days before the Expiration Date. If the notice is not so
given, the Expiration Date shall automatically be extended until 30 days after
the date the Company delivers the notice to Holder.

        4.2 Legends. This Warrant and the Shares (and the securities issuable,
directly or indirectly, upon conversion of the Shares, if any) shall be
imprinted with a legend in substantially the following form:

        THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933,
        AS AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED
        WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT OR PURSUANT TO
        RULE 144 OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
        CORPORATION AND ITS COUNSEL THAT SUCH REGISTRATION IS NOT REQUIRED.

        4.3 Compliance with Securities Laws on Transfer. This Warrant and the
Shares issuable upon exercise this Warrant (and the securities issuable,
directly or indirectly, upon conversion of the Shares, if any) may not be
transferred or assigned in whole or in part without compliance with applicable
federal and state securities laws by the transferor and the transferee
(including, without limitation, the delivery of investment representation
letters and legal opinions reasonably satisfactory to the Company). The Company
shall not require Holder to provide an opinion of counsel if the transfer is to
an affiliate of Holder or if there is no material question as to the
availability of current information as referenced in Rule 144(c), Holder
represents that it has complied with Rule 144(d) and (e) in reasonable detail,
the selling broker represents that it has complied with Rule 144(f), and the
Company is provided with a copy of Holder's notice of proposed sale.

        4.4 Transfer Procedure. Subject to the provisions of Section 4.3, Holder
may transfer all or part of this Warrant or the Shares issuable upon exercise of
this Warrant (or the securities issuable, directly or indirectly, upon
conversion of the Shares, if any) by giving the Company notice of the portion of
the Warrant being transferred setting forth the name, address and taxpayer
identification number of the transferee and surrendering this Warrant to the
Company for reissuance to the transferee(s) (and Holder, if applicable). Unless
the Company is filing financial information with the SEC pursuant to the
Securities Exchange Act of 1934, the

                                       5
<PAGE>

Company shall have the right to refuse to transfer any portion of this Warrant
to any person who directly competes with the Company.

        4.5 Notices. All notices and other communications from the Company to
the Holder, or vice versa, shall be deemed delivered and effective when given
personally or mailed by first-class registered or certified mail, postage
prepaid, at such address as may have been furnished to the Company or the
Holder, as the case may be, in writing by the Company or such Holder from time
to time.

        4.6 Waiver. This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought.

        4.7 Attorneys' Fees. In the event of any dispute between the parties
concerning the terms and provisions of this Warrant, the party prevailing in
such dispute shall be entitled to collect from the other party all costs
incurred in such dispute, including reasonable attorneys' fees.

        4.8 Governing Law. This Warrant shall be governed by and construed in
accordance with the laws of the State of California, without giving effect to
its principles regarding conflicts of law.

                                            WEBSIDESTORY, INC.

                                            By: /s/ JOHN HENTRICH
                                               ---------------------------------

                                            Name:   John Hentrich
                                                 -------------------------------

                                            Title:  President/CEO
                                                  ------------------------------

                                            By: /s/ MICHAEL CHRISTIAN
                                               ---------------------------------

                                            Name:   Michael Christian
                                                 -------------------------------

                                            Title:  SVP
                                                  ------------------------------

                                       6
<PAGE>

                                   APPENDIX 1

                               NOTICE OF EXERCISE

        1. The undersigned hereby elects to purchase __________ shares of the
Common Stock of WEBSIDESTORY, INC. pursuant to the terms of the attached
Warrant, and tenders herewith payment of the purchase price of such shares in
full.

        2. Please issue a certificate or certificates representing said shares
in the name of the undersigned or in such other name as is specified below:

                      Chief Financial Officer
                      Controllers Department
                      Imperial Bancorp
                      P.O. Box 92991
                      Los Angeles, CA 90009
                      Or Registered Assignee

        3. The undersigned represents it is acquiring the shares solely for its
own account and not as a nominee for any other party and not with a view toward
the resale or distribution thereof except in compliance with applicable
securities laws.

IMPERIAL BANCORP  or Registered Assignee

-----------------------------------
(Signature)

-------------------
(Date)

                                       7
<PAGE>

                                   APPENDIX 2

                     NOTICE THAT WARRANT IS ABOUT TO EXPIRE

                          _________________, __________

Chief Financial Officer
Controllers Department
Imperial Bancorp
P.O. Box 92991
Los Angeles, CA 90009
Or Registered Assignee

Gentleperson:

        This is to advise you that the Warrant issued to you described below
will expire on March 26, 2005.

Issuer:                                     WEBSIDESTORY, INC.

Issue Date:                                 March 27, 2000

Class of Security Issuable:                 Common

Exercise Price Per Share:                   $2.50

Number of Shares Issuable:                  80,000

Procedure for Exercise:

        Please contact [name of contact person at (phone number)] with any
questions you may have concerning exercise of the Warrant. This is your only
notice of pending expiration.

        WEBSIDESTORY, INC.

        By:
           -----------------------------

        Its:
            ----------------------------

                                       8
<PAGE>

                                    EXHIBIT B

                               Registration Rights

        The Shares shall be deemed "registrable securities" or otherwise
entitled to "piggy back" registration rights in accordance with the terms of the
following agreement (the "Agreement") between the Company and its investor(s):

               Reg. Rights AGMT. June 18, 1999
               ----------------------------------------------------------------
               [Identify Agreement by date, title and parties.  If no Agreement
               exists, indicate by "none."]

        The Company agrees that no amendments will be made to the Agreement
which would have an adverse impact on Holder's registration thereunder without
the consent of Holder. By acceptance of the Warrant to which this Exhibit B is
attached, Holder shall not be deemed to be a party to the Agreement, but solely
entitled to the registration rights created thereby.

        If no Agreement exists, then the Company and the Holder shall enter into
Holder's standard form of Registration Rights Agreement as in effect on the
Issue Date of the Warrant.

                                       9
<PAGE>

                              AMENDMENT TO WARRANT

      This Amendment to Warrant is entered into on August 21th, 2000, by and
between WEBSIDESTORY, INC. ("Company") and IMPERIAL BANCORP, ("Holder").

      Holder was issued a warrant dated March 27, 2000 by Company (the
"Warrant") and in connection with an additional extension of credit by Imperial
Bank, Company agreed to amend the Initial Exercise Price of the Shares specified
therein.

      In consideration of the additional extension of credit and the provisions
hereof, it is agreed as follows:

      1. The Initial Exercise Price is hereby amended to be $1.35.

      2. Except as amended hereby, the terms and provisions of the are ratified
and confirmed and are in full force and effect.

      This Amendment is executed by duly authorized persons as of the date first
above written.

                                  WEBSIDESTORY, INC.

                                  By: /s/ [ILLEGIBLE]
                                     -------------------------------------------
                                  Title: SRVP CFO

                                  By: /s/ John Hentrich
                                     -------------------------------------------
                                  Title: CEO

                                  IMPERIAL BANCORP

                                  By: /s/ [ILLEGIBLE]
                                  Title:VP

                                  By: __________________________________________
                                  Title: _______________________________________

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