<PAGE>   1

                                                                    EXHIBIT 4.10


                            BROADBASE SOFTWARE, INC.
                         NON-PLAN STOCK OPTION AGREEMENT

               This Stock Option Agreement (this "AGREEMENT") is made and
entered into as of the date of grant set forth below (the "DATE OF GRANT") by
and between Broadbase Software, Inc., a Delaware corporation (the "COMPANY"),
and the optionee named below ("OPTIONEE"). Capitalized terms not defined herein
shall have the meaning ascribed to them in Section 20.

<TABLE>
<S>                                   <C>
OPTIONEE:                             David Milam

SOCIAL SECURITY NUMBER:               ###-##-####

OPTIONEE'S ADDRESS:                   360 Montserrat Drive
                                      Redwood City, CA 94065

TOTAL OPTION SHARES:                  400,000

EXERCISE PRICE PER SHARE:             $14.5156

DATE OF GRANT:                        4/24/2000

VESTING START DATE:                   4/5/2000

EXPIRATION DATE:                      4/24/2010

TYPE OF STOCK OPTION:                 Nonqualified Stock Option
</TABLE>

               1.     GRANT OF OPTION. The Company hereby grants to Optionee an
option (this "OPTION") to purchase up to the total number of shares of common
stock of the Company, $0.001 par value ("COMMON STOCK"), set forth above
(collectively, the "SHARES") at the Exercise Price Per Share set forth above
(the "EXERCISE PRICE"), subject to all of the terms and conditions of this
Agreement.

               2.     VESTING; EXERCISE PERIOD.

                      2.1    Vesting of Shares. This Option shall be exercisable
as it vests. Subject to the terms and conditions of this Agreement, this Option
shall vest and become exercisable as to portions of the Shares as follows: (a)
this Option shall not be exercisable with respect to any of the Shares until
July 5, 2000 (the "FIRST VESTING DATE"); (b) if Optionee has continuously
provided services to the Company, or any Parent or Subsidiary of the Company,
then on the First Vesting Date, this Option shall become exercisable as to 6.25%
of the Shares; and (c) thereafter this Option shall become exercisable as to an
additional 2.083% of the Shares on each monthly anniversary of the First Vesting
Date, provided that Optionee has continuously provided services to the Company,
or any Parent or Subsidiary of the Company. Furthermore, in the event of a
change in control of at least 50% of the voting stock of the company, in
conjunction with the optionee's termination or constructive termination, then
50% of the unvested shares shall immediately vest. This Option shall cease to
vest upon Optionee's Termination and Optionee shall in no event be entitled
under this Option to purchase a number of shares of the Company's Common Stock
greater than the "Total Option Shares."

                      2.2    Expiration. This Option shall expire on the
Expiration Date set forth above and must be exercised, if at all, on or before
the earlier of the Expiration Date or the date on which this Option is earlier
terminated in accordance with the provisions of Section 3, provided, however,
that this Option will be not be exercisable after the expiration of ten (10)
years from the Date of Grant.


<PAGE>   2

               3.     TERMINATION.

                      3.1    Termination for Any Reason Except Death, Disability
or Cause. If Optionee is Terminated for any reason except Optionee's death,
Disability or Cause, then this Option, to the extent (and only to the extent)
that it is vested in accordance with the schedule set forth in Section 2.1 of
this Agreement on the date of Termination, may be exercised by Optionee no later
than three (3) months after the date of Termination, but in any event no later
than the Expiration Date.

                      3.2    Termination Because of Death or Disability. If
Optionee is Terminated because of death or Disability of Optionee (or the
Optionee dies within three (3) months after a Termination other than because of
death, Disability or Cause), then this Option, to the extent that it is vested
in accordance with the schedule set forth in Section 2.1 of this Agreement on
the date of Termination, may be exercised by Optionee (or Optionee's legal
representative) no later than twelve (12) months after the date of Termination,
but in any event no later than the Expiration Date.

                      3.3    Termination for Cause. If Optionee is Terminated
for Cause, this Option will expire on the Optionee's date of Termination.

                      3.4    No Obligation to Employ. Nothing in this Agreement
shall confer on Optionee any right to continue in the employ of, or other
relationship with, the Company or any Parent or Subsidiary of the Company, or
limit in any way the right of the Company or any Parent or Subsidiary of the
Company to terminate Optionee's employment or other relationship at any time,
with or without Cause.

               4.     MANNER OF EXERCISE.

                      4.1    Stock Option Exercise Agreement. To exercise this
Option, Optionee (or in the case of exercise after Optionee's death, Optionee's
executor, administrator, heir or legatee, as the case may be) must deliver to
the Company an executed stock option exercise agreement in the form attached
hereto as Exhibit A, or in such other form as may be approved by the Company
from time to time (the "EXERCISE Agreement"), which shall set forth, inter alia,
Optionee's election to exercise this Option, the number of shares being
purchased, any restrictions imposed on the Shares and any representations,
warranties and agreements regarding Optionee's investment intent and access to
information as may be required by the Company to comply with applicable
securities laws. If someone other than Optionee exercises this Option, then such
person must submit documentation reasonably acceptable to the Company that such
person has the right to exercise this Option.

                      4.2    Limitations on Exercise. This Option may not be
exercised unless such exercise is in compliance with all applicable federal and
state securities laws, as they are in effect on the date of exercise. This
Option may not be exercised as to fewer than 100 Shares unless it is exercised
as to all Shares as to which this Option is then exercisable.

                      4.3    Payment. The Exercise Agreement shall be
accompanied by full payment of the Exercise Price for the Shares being purchased
in cash (by check), or where permitted by law:

        (a)    provided that a public market for the Company's stock exists: (1)
               through a "same day sale" commitment from Optionee and a
               broker-dealer that is a member of the National Association of
               Securities Dealers (an "NASD DEALER") whereby Optionee
               irrevocably elects to exercise this Option and to sell a portion
               of the Shares so purchased to pay for the exercise price and
               whereby the NASD Dealer irrevocably commits upon receipt of such
               Shares to forward the exercise price directly to the Company; or
               (2) through a "margin" commitment from Optionee and a NASD --
               Dealer whereby Optionee irrevocably elects to exercise this
               Option and to pledge the Shares so purchased to the NASD Dealer
               in a margin account as security for a loan from the NASD Dealer
               in the amount of the exercise price, and whereby the NASD Dealer
               irrevocably commits upon receipt of such Shares to forward the
               exercise price directly to the Company; or


<PAGE>   3

        (b)    by any combination of the foregoing.

                      4.4    Tax Withholding. Prior to the issuance of the
Shares upon exercise of this Option, Optionee must pay or provide for any
applicable federal or state withholding obligations of the Company. If the
Committee permits, Optionee may provide for payment of withholding taxes upon
exercise of this Option by requesting that the Company retain Shares with a Fair
Market Value equal to the minimum amount of taxes required to be withheld. In
such case, the Company shall issue the net number of Shares to the Optionee by
deducting the Shares retained from the Shares issuable upon exercise.

                      4.5    Issuance of Shares. Provided that the Exercise
Agreement and payment are in form and substance satisfactory to counsel for the
Company, the Company shall issue the Shares registered in the name of Optionee,
Optionee's authorized assignee, or Optionee's legal representative, and shall
deliver certificates representing the Shares with the appropriate legends
affixed thereto.

               5.     COMPLIANCE WITH LAWS AND REGULATIONS. The exercise of this
Option and the issuance and transfer of Shares shall be subject to compliance by
the Company and Optionee with all applicable requirements of federal and state
securities laws and with all applicable requirements of any stock exchange on
which the Company's Common Stock may be listed at the time of such issuance or
transfer. Optionee understands that the Company is under no obligation to
register or qualify the Shares with the Securities and Exchange Commission, any
state securities commission or any stock exchange to effect such compliance.

               6.     NONTRANSFERABILITY OF OPTION. This Option may not be
transferred in any manner other than by will or by the laws of descent and
distribution and may be exercised during the lifetime of Optionee only by
Optionee. The terms of this Option shall be binding upon the executors,
administrators, successors and assigns of Optionee.

               7.     TAX CONSEQUENCES. Set forth below is a brief summary of
some of the federal and California tax consequences of exercise of this Option
and disposition of the Shares. THIS SUMMARY IS NECESSARILY INCOMPLETE, AND THE
TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. OPTIONEE SHOULD CONSULT A TAX
ADVISOR BEFORE EXERCISING THE OPTION OR DISPOSING OF THE SHARES.

                      7.1    Exercise of Nonqualified Stock Option. There may be
a regular federal and California income tax liability upon the exercise of this
Option. Optionee will be treated as having received compensation income (taxable
at ordinary income tax rates) equal to the excess, if any, of the fair market
value of the Shares on the date of exercise over the Exercise Price. The Company
will be required to withhold from Optionee's compensation or collect from
Optionee and pay to the applicable taxing authorities an amount equal to a
percentage of this compensation income at the time of exercise.

                      7.2    Disposition of Shares. If the Shares are held for
more than twelve (12) months after the date of the transfer of the Shares
pursuant to the exercise of an NQSO, any gain realized on disposition of the
Shares will be treated as long-term capital gain, as the case may be.

               8.     PRIVILEGES OF STOCK OWNERSHIP. Optionee shall not have any
of the rights of a shareholder with respect to any Shares until Optionee
exercises this Option and pays the Exercise Price.

               9.     INTERPRETATION. Any dispute regarding the interpretation
of this Agreement shall be submitted by Optionee or the Company to the Committee
for review. The resolution of such a dispute by the Committee shall be final and
binding on the Company and Optionee.


<PAGE>   4

               10.    ENTIRE AGREEMENT. This Agreement and the Exercise
Agreement constitute the entire agreement and understanding of the parties
hereto with respect to the subject matter hereof and supersede all prior
understandings and agreements with respect to such subject matter.

               11.    NOTICES. Any notice required to be given or delivered to
the Company under the terms of this Agreement shall be in writing and addressed
to the Corporate Secretary of the Company at its principal corporate offices.
Any notice required to be given or delivered to Optionee shall be in writing and
addressed to Optionee at the address indicated above or to such other address as
such party may designate in writing from time to time to the Company. All
notices shall be deemed to have been given or delivered upon: personal delivery;
three (3) days after deposit in the United States mail by certified or
registered mail (return receipt requested); one (1) business day after deposit
with any return receipt express courier (prepaid); or one (1) business day after
transmission by rapifax or telecopier.

               12.    SUCCESSORS AND ASSIGNS. The Company may assign any of its
rights under this Agreement. This Agreement shall be binding upon and inure to
the benefit of the successors and assigns of the Company. Subject to the
restrictions on transfer set forth herein, this Agreement shall be binding upon
Optionee and Optionee's heirs, executors, administrators, legal representatives,
successors and assigns.

               13.    GOVERNING LAW. This Agreement shall be governed by and
construed in accordance with the internal laws of the State of California,
without regard to that body of law pertaining to choice of law or conflict of
law.

               14.    ACCEPTANCE. Optionee hereby acknowledges receipt of a copy
of this Agreement. Optionee has read and understands the terms and provisions
thereof, and accepts this Option subject to all the terms and conditions of this
Agreement. Optionee acknowledges that there may be adverse tax consequences upon
exercise of this Option or disposition of the Shares and that the Company has
advised Optionee to consult a tax advisor prior to such exercise or disposition.

               15.    MODIFICATION, EXTENSION OR RENEWAL. The Committee may
modify, extend or renew this Option and authorize the grant of new options in
substitution therefor, provided that any such action may not, without the
written consent of the Optionee, impair any of such Optionee's rights under this
Option. The Committee may reduce the Exercise Price of this Option without the
consent of the Optionee affected by a written notice to them; provided, however,
that the Exercise Price may not be reduced below 85% of the Fair Market Value of
the Shares on the date of grant.

               16.    CERTIFICATES. All certificates for Shares or other
securities delivered upon exercise of this Option will be subject to such stock
transfer orders, legends and other restrictions as the Committee may deem
necessary or advisable, including restrictions under any applicable federal,
state or foreign securities law, or any rules, regulations and other
requirements of the SEC or any stock exchange or automated quotation system upon
which the Shares may be listed or quoted.

               17.    ADJUSTMENT OF SHARES. In the event that the number of
outstanding shares is changed by a stock dividend, recapitalization, stock
split, reverse stock split, subdivision, combination, reclassification or
similar change in the capital structure of the Company without consideration,
then the Exercise Price of and the number of Shares subject to this Option will
be proportionately adjusted, subject to any required action by the Board or the
Optionee and compliance with applicable securities laws; provided, however, that
fractions of a Share will not be issued but will either be replaced by a cash
payment equal to the Fair Market Value of such fraction of a Share or will be
rounded up to the nearest whole Share, as determined by the Committee.

               18.    CORPORATE TRANSACTIONS.

                      18.1   Assumption or Replacement of Option by Successor.
In the event of (a) a dissolution or liquidation of the Company, (b) a merger or
consolidation in which the Company is not the surviving


<PAGE>   5

corporation (other than a merger or consolidation with a wholly-owned
subsidiary, a reincorporation of the Company in a different jurisdiction, or
other transaction in which there is no substantial change in the stockholders of
the Company or their relative stock holdings and this Option is assumed,
converted or replaced by the successor corporation, which assumption will be
binding on the Optionee), (c) a merger in which the Company is the surviving
corporation but after which the stockholders of the Company immediately prior to
such merger (other than any stockholder that merges, or which owns or controls
another corporation that merges, with the Company in such merger) cease to own
their shares or other equity interest in the Company, (d) the sale of
substantially all of the assets of the Company, or (e) the acquisition, sale, or
transfer of more than 50% of the outstanding shares of the Company by tender
offer or similar transaction, this Option may be assumed, converted or replaced
by the successor corporation (if any), which assumption, conversion or
replacement will be binding on the Optionee. In the alternative, the successor
corporation may substitute equivalent options or provide substantially similar
consideration to the Optionee as was provided to other stockholders. The
successor corporation may also issue, in place of outstanding Shares of the
Company held by the Optionee, substantially similar shares or other property
subject to repurchase restrictions no less favorable to the Optionee. In the
event such successor corporation (if any) refuses to assume or substitute this
Option, as provided above, pursuant to a transaction described in this
subsection, this Option will expire on such transaction at such time and on such
conditions as the Committee will determine; provided, however, that the
Committee may, in its sole discretion, provide that the vesting of this Option
will accelerate. If the Committee exercises such discretion with respect to this
Option, this Option will become exercisable in full prior to the consummation of
such event at such time and on such conditions as the Committee determines, and
if this Option is not exercised prior to the consummation of the corporate
transaction, it shall terminate at such time as determined by the Committee.

                      18.2   Other Treatment of Option. Subject to any greater
rights granted to the Optionee under the foregoing provisions of this section,
in the event of the occurrence of any transaction described in Section 18.1,
this Option will be treated as provided in the applicable agreement or plan of
merger, consolidation, dissolution, liquidation, or sale of assets.

               19.    AMENDMENT OR TERMINATION OF THE AGREEMENT. The Board may
at any time terminate or amend this Agreement in any respect; provided, however,
that the Board will not, without the approval of the Optionee, amend this
Agreement in any manner that requires Optionee's approval.

               20.    DEFINITIONS. As used in this Agreement, the following
terms will have the following meanings:

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

                      "CAUSE" means the commission of an act of theft,
embezzlement, fraud, dishonesty or a breach of fiduciary duty to the Company or
a Parent or Subsidiary of the Company.

                      "COMMITTEE" means the Compensation Committee of the Board

                      "DISABILITY" means a disability, whether temporary or
permanent, partial or total, within the meaning of Section 22(e)(3) of the
Internal Revenue Code of 1986, as amended, as determined by the Committee.

                      "FAIR MARKET VALUE" means, as of any date, the value of a
share of the Company's Common Stock determined as follows:

               (a)    if such Common Stock is then quoted on the Nasdaq National
                      Market, its closing price on the Nasdaq National Market on
                      the date of determination as reported in The Wall Street
                      Journal;

               (b)    if such Common Stock is publicly traded and is then listed
                      on a national securities exchange, its closing price on
                      the date of determination on the principal national
                      securities


<PAGE>   6

                      exchange on which the Common Stock is listed or admitted
                      to trading as reported in The Wall Street Journal;

               (c)    if such Common Stock is publicly traded but is not quoted
                      on the Nasdaq National Market nor listed or admitted to
                      trading on a national securities exchange, the average of
                      the closing bid and asked prices on the date of
                      determination as reported in The Wall Street Journal; or

               (d)    if none of the foregoing is applicable, by the Committee
                      in good faith.

                      "PARENT" means any corporation (other than the Company) in
an unbroken chain of corporations ending with the Company if each of such
corporations other than the Company owns stock possessing 50% or more of the
total combined voting power of all classes of stock in one of the other
corporations in such chain.

                      "SUBSIDIARY" means any corporation (other than the
Company) in an unbroken chain of corporations beginning with the Company if each
of the corporations other than the last corporation in the unbroken chain owns
stock possessing 50% or more of the total combined voting power of all classes
of stock in one of the other corporations in such chain.

                      "TERMINATION" or "TERMINATED" means, for purposes of this
Agreement with respect to the Optionee, that the Optionee has for any reason
ceased to provide services as an employee, officer, director, consultant,
independent contractor, or advisor to the Company or a Parent or Subsidiary of
the Company. An employee will not be deemed to have ceased to provide services
in the case of (i) sick leave, (ii) military leave, or (iii) any other leave of
absence approved by the Committee, provided, that such leave is for a period of
not more than 90 days, unless reemployment upon the expiration of such leave is
guaranteed by contract or statute or unless provided otherwise pursuant to
formal policy adopted from time to time by the Company and issued and
promulgated to employees in writing. In the case of the Optionee is on an
approved leave of absence, the Committee may make such provisions respecting
suspension of vesting of this Option while on leave from the employ of the
Company or a Subsidiary as it may deem appropriate, except that in no event may
this Option be exercised after the expiration of the term set forth in this
Agreement. The Committee will have sole discretion to determine whether the
Optionee has ceased to provide services and the effective date on which the
Optionee ceased to provide services (the "TERMINATION DATE").

            IN WITNESS WHEREOF, the Company has caused this Agreement to be
executed in duplicate by its duly authorized representative and Optionee has
executed this Agreement in duplicate as of the Date of Grant.

BROADBASE SOFTWARE, INC.                       OPTIONEE


By: /s/ RUSTY THOMAS                           /s/ DAVID MILAM
    ------------------------------             --------------------------------
                                               (Signature)

Rusty Thomas                                   David Milam
----------------------------------             --------------------------------
(Please print name)                            (Please print name)

Executive Vice President & CFO
---------------------------------
(Please print title)


<PAGE>   7


                            BROADBASE SOFTWARE, INC.
                    NON-PLAN STOCK OPTION EXERCISE AGREEMENT

         I hereby elect to purchase the number of shares of Common Stock of
BROADBASE SOFTWARE, INC. (the "Company") as set forth below:

<TABLE>
<S>                                                  <C>
Optionee                                             Number of Shares Purchased:
        ---------------------------------------                                 ---------------------

Social Security Number:                              Purchase Price per Share:
                       ------------------------                               -----------------------

Address:                                             Aggregate Purchase Price:
        ---------------------------------------                               -----------------------

        ---------------------------------------      Date of Option Agreement:
                                                                              -----------------------

Type of Option:  Nonqualified Stock Option           ------------------------------------------------
                 ------------------------------
                                                     Exact Name of Title to Shares:
                                                                                   ------------------

                                                     ------------------------------------------------
</TABLE>

1.      DELIVERY OF PURCHASE PRICE. Optionee hereby delivers to the Company the
Aggregate Purchase Price, to the extent permitted in the Option Agreement (the
"Option Agreement") as follows (check as applicable and complete):

[ ]  in cash (by check) in the amount of $__________________, receipt of which
     is acknowledged by the Company;

[ ]  through a "same-day-sale" commitment, delivered herewith, from Optionee
     and the NASD Dealer named therein, in the amount of $_________________; or

[ ]  through a "margin" commitment, delivered herewith from Optionee and the
     NASD Dealer named therein, in the amount of $_____________________.

2.      MARKET STANDOFF AGREEMENT. Optionee, if requested by the Company and an
underwriter of Common Stock (or other securities) of the Company, agrees not to
sell or otherwise transfer or dispose of any Common Stock (or other securities)
of the Company held by Optionee during the period requested by the managing
underwriter following the effective date of a registration statement of the
Company filed under the Securities Act, provided that all officers and directors
of the Company are required to enter into similar agreements. Such agreement
shall be in writing in a form satisfactory to the Company and such underwriter.
The Company may impose stop-transfer instructions with respect to the shares (or
other securities) subject to the foregoing restriction until the end of such
period.

3.      TAX CONSEQUENCES. OPTIONEE UNDERSTANDS THAT OPTIONEE MAY SUFFER ADVERSE
TAX CONSEQUENCES AS A RESULT OF OPTIONEE'S PURCHASE OR DISPOSITION OF THE
SHARES. OPTIONEE REPRESENTS THAT OPTIONEE HAS CONSULTED WITH ANY TAX
CONSULTANT(S) OPTIONEE DEEMS ADVISABLE IN CONNECTION WITH THE PURCHASE OR
DISPOSITION OF THE SHARES AND THAT OPTIONEE IS NOT RELYING ON THE COMPANY FOR
ANY TAX ADVICE.

4.      ENTIRE AGREEMENT. The Option Agreement is incorporated herein by
reference. This Exercise Agreement and the Option Agreement constitute the
entire agreement and understanding of the parties and supersede in their
entirety all prior understandings and agreements of the Company and Optionee
with respect to the subject matter hereof, and are governed by California law
except for that body of law pertaining to choice of law or conflict of law.



Date:_____________________              __________________________________
                                        SIGNATURE OF OPTIONEE