<PAGE>

                                                                   Exhibit 10.27

    NEITHER THIS WARRANT NOR THE SHARES ISSUABLE UPON EXERCISE OF THIS WARRANT
HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND NEITHER
THIS WARRANT NOR THE SHARES ISSUABLE UPON EXERCISE OF THIS WARRANT MAY BE SOLD
OR TRANSFERRED UNLESS THE REGISTRATION PROVISIONS OF SAID ACT HAVE BEEN COMPLIED
WITH OR UNLESS COMPLIANCE WITH SUCH PROVISIONS IS NOT REQUIRED.


No. AC-3                                              Dated:  December 9, 1999


                              PRIME RESPONSE, INC.

                                  COMMON STOCK
                                PURCHASE WARRANT


          THIS IS TO CERTIFY THAT, for value received, Andersen Consulting LLP
(the "Initial Warrant Holder"), and its registered successors and permitted
assigns are entitled, subject to the terms and conditions set forth below, to
purchase from PRIME RESPONSE, INC. (f/k/a Prime Response Group, Inc.), a
Delaware corporation (the "Corporation"), at any time or from time to time on
and after the date hereof and prior to 5:00 P.M., Boston, Massachusetts time, on
the Expiration Date (as defined in Section 1 below), all or any portion of the
Warrant Shares (as defined in Section 1), at a purchase price per share equal to
the Exercise Price (as defined in Section 1 below).  The number and character of
the Warrant Shares and the Exercise Price are subject to adjustment as provided
herein.

          1.  DEFINITIONS.  As used in this Warrant, the following terms shall
have the respective meanings set forth below or elsewhere in this Warrant as
referred to below:

          "Certificate of Incorporation" shall mean the Certificate of
Incorporation of the Corporation, as amended and in effect from time to time.

          "Common Stock" shall mean shares of the Common Stock of the
Corporation, $0.01 par value per share of the Corporation and shall also include
any capital stock of any class of the Corporation authorized after the date
hereof which shall neither be limited to a fixed sum or percentage of par value
in respect of the rights of the holders  thereof to participate in dividends or
any distribution of earnings or assets (in liquidation or otherwise) of the
Corporation, whether or not such capital stock is entitled to a
<PAGE>

preference in the distribution of assets upon the voluntary of involuntary
liquidation, dissolution or winding up of the Corporation.


          "Corporation" shall mean Prime Response, Inc. and/or any Person that
shall succeed to, or assume the obligations hereunder of, Prime Response, Inc.

          "Derivative Securities" shall mean (i) all shares of stock and other
securities that are, directly or indirectly, convertible into or exchangeable
for shares of Common Stock and (ii) all options, warrants and other rights to
acquire, directly or indirectly, shares of Common Stock or securities, directly
or indirectly, convertible into or exchangeable for shares of Common Stock.

          "Exercise Date" shall have the meaning set forth in Section 2.2
hereof.

          "Exercise Price" shall mean, as of the Initial Exercise Date, the
Initial Exercise Price and after the Initial Exercise Date, the Initial Exercise
Price as adjusted from time to time pursuant to the terms of this Warrant.

          "Expiration Date" shall mean December 9, 2006.

          "Fair Market Value" shall mean (i) the last reported sale price per
share of Stock on the Nasdaq National Market or any national securities exchange
in which such Stock is quoted or listed, as the case may be, on the date
immediately preceding the Exercise Date or, if no such sale price is reported on
such date, such price on the next preceding business day in which such price was
reported, or (ii) if such Stock is not quoted or listed on the Nasdaq National
Market or any national securities exchange, the fair market value of a share of
such Stock, as determined in good faith by the Board of Directors of the
Corporation and based upon the fair market value of the Corporation as a whole,
(and not taking into account any discounts for minority ownership or
restrictions or transfer of capital stock of the Corporation).

          "Holder" shall mean, as applicable, (i) the Initial Warrant Holder, or
(ii) any successor of the Initial Warrant Holder.

          "Initial Exercise Date" shall mean the date on which this Warrant
first vests in accordance with the provisions of the second paragraph of Section
2.1 hereof.

          "Initial Exercise Price" shall mean an amount equal to $7.01 per
share.

          "Initial Warrant Holder" shall have the meaning set forth in the first
paragraph of this Warrant.

          "Initial Warrant Shares" shall mean 500,000 shares of Common Stock.

                                      -2-
<PAGE>

          "Issue Date" shall mean the date hereof.

          "Person" shall mean an individual, partnership, corporation, limited
liability company, business trust, joint stock company, trust, unincorporated
association, joint venture, governmental authority or other entity of whatever
nature.

          "Preferred Stock" shall mean the Series A Preferred Stock, the Series
B Preferred Stock and the Series C Preferred Stock and all other capital stock
of the Corporation having a preference on dissolution or liquidation of the
Corporation.

          "Purchase Agreement" shall mean that certain Common Stock and Warrant
Purchase Agreement, dated of December 6, 1999, by and between the Corporation
and Andersen Consulting LLP.

          "Registrable Securities" shall have the meaning ascribed to it in the
Registration Rights Agreement.

          "Registration Rights Agreement" shall mean the Amended and Restated
Registration Rights Agreement, dated as of December 6, 1999, by and among the
Corporation and the other parties hereto.

          "Securities Act" shall mean the Securities Act of 1933, as amended.

          "Series A Preferred Stock" shall mean the Series A Convertible
Participating Preferred Stock of the Corporation, $0.01 par value per share.

          "Series B Preferred Stock" shall mean the Series B Convertible
Participating Preferred Stock of the Corporation, $0.01 par value per share.

          "Series C Preferred Stock" shall mean the Series C Convertible
Preferred Stock of the Corporation, $0.01 par value per share.

          "Stock" shall mean (i) Common Stock, (ii) capital stock of the
Corporation (other than Common Stock) or of any other Person or any other
securities of the Corporation or of any other Person that the Holder is entitled
to receive, or receives, upon exercise of this Warrant, in lieu of or in
addition to Common Stock, and/or (iii) capital stock of the Corporation (other
than Common Stock) or of any other Person or any other securities of the
Corporation or of any other Person that may be issued in replacement of,
substitution, exchange or redemption for, or upon reclassification or conversion
of, Common Stock or any other Stock, in each case whether as a result of a
reorganization, reclassification, merger, consolidation or sale of substantially
all of the assets of the Corporation.

                                      -3-
<PAGE>

          "Warrant" shall have the meaning set forth in the second paragraph of
this Warrant.

          "Warrant Shares" shall mean, at any time, the Initial Warrant Shares
after giving effect to the number of shares of Stock previously purchased by the
Holder pursuant to any and all exercises of this Warrant prior to such time and
after giving effect to all adjustments with respect to the number of Warrant
Shares purchaseable hereunder as provided for herein, including, without
limitation, those set forth in Section 4 hereof, prior to such time.

          2. EXERCISE OF WARRANT.

          2.1  METHOD OF EXERCISE.  Subject to and upon all of the terms and
conditions set forth in this Warrant, the Holder may exercise this Warrant, in
whole or in part with respect to any Warrant Shares, at any time and from time
to time during the period commencing on the date that this Warrant vests in
accordance with the second paragraph of this Section 2.1 and ending at 5:00
p.m., Boston, Massachusetts time, on the Expiration Date, by presentation and
surrender of this Warrant to the Corporation at its principal office, together
with (a) a properly completed and duly executed subscription form, in the form
attached hereto, which subscription form shall specify the number of Warrant
Shares for which this Warrant is then being exercised, and (b) payment of the
aggregate Exercise Price payable hereunder in respect of the number of Warrant
Shares being purchased upon exercise of this Warrant.  Payment of such aggregate
Exercise Price shall be made (i) in cash or by money order, certified or bank
cashier's check or wire transfer (in each case in lawful currency of the United
States of America), (ii) by cancellation of indebtedness owing from the
Corporation to the Holder, (iii) if the Common Stock is then traded on the
Nasdaq National Market or a national securities exchange, by cancellation of a
portion of this Warrant exercisable for such number of Warrant Shares as is
determined by dividing (A) the total Exercise Price payable in respect of the
number of Warrant Shares being purchased upon such exercise by (B) the excess of
the Fair Market Value per share of Common Stock as of the Exercise Date (as
defined below) over the Exercise Price per share; if the Holder wishes to
exercise this Warrant pursuant to this clause (iii) with respect to the maximum
number of Warrant Shares purchasable pursuant to this method, then the number of
Warrant Shares so purchased shall be equal to the total number of Warrant
Shares, minus the product obtained by multiplying (x) the total number of
Warrant Shares by (y) a fraction, the numerator of which shall be the Exercise
Price per share and the denominator of which shall be the Fair Market Value per
share of Common Stock as of the Exercise Date, or (iv) any combination of the
methods described in the foregoing clauses (i), (ii) or (iii).

     This Warrant will become exercisable ("vest") based on the Product Revenue
("Product Revenue") achieved under the Marketing Agreement (the "Marketing
Agreement") dated the date hereof between the Company and Andersen Consulting
LLP ("Andersen") that

                                      -4-
<PAGE>

is attributable to joint marketing efforts of the Company and Andersen pursuant
to Section 2.3 of such Marketing Agreement, as follows:


<TABLE>
<CAPTION>
        Product Revenue                                 Warrants Becoming Exercisable
        -----------------                               -----------------------------
<S>                                                    <C>
        First $25 million                               14,000 for each $1 million of sales revenue

        Next $25 million                                6,000 for each $1 million of sales revenue
</TABLE>

     Product Revenue shall be determined in accordance with the procedures set
forth in Sections 4.3 and 4.4 of the Marketing Agreement.  Once this Warrant
becomes exercisable with respect to Warrant Shares in accordance with the
foregoing provisions, this Warrant shall not cease to be exercisable with
respect to such Warrant Shares as a result of the Product Revenue decreasing
below the amount that resulted in this Warrant (or any portion hereof) becoming
exercisable.

     In no event shall this Warrant become exercisable for more than 500,000
shares of Common Stock.  Notwithstanding anything to the contrary contained
herein, upon termination of the Marketing Agreement at the election of the
Company as a result of a breach by Andersen pursuant to Section 10.2(a) thereof,
no further vesting of this Warrant shall occur, but the Warrant shall remain
exercisable during its term to the extent then vested.

     2.2  EFFECTIVENESS OF EXERCISE; OWNERSHIP.  Each exercise of this Warrant
          ------------------------------------
by the Holder shall be deemed to have been effected immediately prior to the
close of business on the date upon which all of the requirements of Section 2.1
hereof with respect to such exercise shall have been complied with in full (each
such date, an "Exercise Date").  On the applicable Exercise Date with respect to
               -------------
any exercise of this Warrant by the Holder, the Corporation shall be deemed to
have issued to the Holder, and the Holder shall be deemed to have become the
holder of record and legal owner of, the number of Warrant Shares being
purchased upon such exercise of this Warrant, notwithstanding that the stock
transfer books of the Corporation shall then be closed or that certificates
representing such number of Warrant Shares being purchased shall not then be
actually delivered to the Holder.

          2.3  DELIVERY OF STOCK CERTIFICATES ON EXERCISE.  As soon as
practicable after the exercise of this Warrant, and in any event within ten (10)
days thereafter, the Corporation, at its expense and in accordance with
applicable securities laws, will cause to be issued in the name of and delivered
to the Holder, or as the Holder may direct (subject in all cases, to the
provisions of Section 9 hereof), a certificate or certificates for the number of
Warrant Shares purchased by the Holder on such exercise, plus, in lieu of any
fractional share to which the Holder would otherwise be entitled, cash equal to
such fraction multiplied by the Fair Market Value.

                                      -5-
<PAGE>

          2.4  SHARES TO BE FULLY PAID AND NONASSESSABLE.  All Warrant Shares
issued upon the exercise of this Warrant shall be validly issued, fully paid and
nonassessable, free of all liens, taxes, charges and other encumbrances or
restrictions on sale (other than those set forth herein) and free and clear of
all preemptive rights.

          2.5  FRACTIONAL SHARES.  No fractional shares of Stock or scrip
representing fractional shares of Stock shall be issued upon the exercise of
this Warrant.  With respect to any fraction of a share of Stock called for upon
any exercise hereof, the Corporation shall make a cash payment to the Holder as
set forth in Section 2.3 hereof.

          2.6  ISSUANCE OF NEW WARRANTS; CORPORATION ACKNOWLEDGMENT.  Upon any
partial exercise of this Warrant, the Corporation, at its expense, will
forthwith and, in any event, within ten (10) days after such partial exercise
issue and deliver to the Holder a new warrant or warrants of like tenor,
registered in the name of the Holder, exercisable, in the aggregate, for the
balance of the Warrant Shares.

          2.7  PAYMENT OF TAXES AND EXPENSES.  The Corporation shall pay any
recording, filing, stamp or similar tax which may be payable in respect of any
transfer involved in the issuance of, and the preparation and delivery of
certificates (if applicable) representing, (i) any Warrant Shares purchased upon
exercise of this Warrant and/or (ii) new or replacement warrants in the Holder's
name or the name of any transferee of all or any portion of this Warrant.

     3.  REGISTRATION AND OTHER RIGHTS.

          (a) REGISTRATION RIGHTS.  The Holder of this Warrant shall have the
right to cause the Corporation to register any and all Warrant Shares under the
Securities Act and under any blue sky or securities laws of any jurisdictions
within the United States, at the time and in the manner specified and as
provided for in the Registration Rights Agreement, and any and all Warrant
Shares shall be deemed to be included within the definition of Registrable
Securities for all purposes thereof.

          (b) PURCHASE AGREEMENT.  Subject to Section 10.4 of this Warrant, for
the purposes of the Purchase Agreement, the shares of Common Stock issuable upon
exercise of this Warrant shall be included for the purposes of determining the
number of shares of Common Stock held by such Holder for all purposes of such
agreement.

     4.  ADJUSTMENTS.

     4.1 ADJUSTMENTS FOR STOCK DIVIDENDS, SUBDIVISIONS AND COMBINATIONS.

          (a) In the event that, at any time and from time to time after the
Issue Date, the Corporation shall (A) issue any additional shares of Stock as a
dividend or

                                      -6-
<PAGE>

distribution on its outstanding Stock or options, warrants or other rights to
purchase, directly or indirectly, Stock as a dividend or distribution on its
outstanding Stock or securities convertible, directly or indirectly, into Stock
as a dividend or distribution on its outstanding Stock (other than shares of
Stock issued upon conversion of Preferred Stock), (B) subdivide its outstanding
shares of Stock into a greater number of shares of Stock or (C) combine its
outstanding shares of Stock into a smaller number of shares of Stock, then and
in each such event, (x) the Exercise Price shall, simultaneously with the
happening of such event, be adjusted by multiplying the then current Exercise
Price by a fraction, (i) the numerator of which shall be the number of shares of
Stock outstanding immediately prior to such event on a fully-diluted basis,
assuming exercise in full of all options, warrants or other rights to purchase
Stock, directly or indirectly, outstanding immediately prior to such event and
conversion into or exchange for Stock, directly or indirectly, of all securities
convertible into or exchangeable for Stock outstanding immediately prior to such
event, each in accordance with their terms, and (ii) the denominator of which
shall be the number of shares of Stock outstanding immediately after such event
on a fully-diluted basis, assuming exercise in full of all options, warrants or
other rights to purchase Stock, directly or indirectly, outstanding immediately
after such event and conversion into or exchange for Stock, directly or
indirectly, of all securities convertible into or exchangeable for Stock
outstanding immediately after such event, each in accordance with their terms,
and the product so obtained shall thereafter be the Exercise Price then in
effect, and (y) the number of Warrant Shares shall be adjusted by increasing or
decreasing, as the case may be, the number of shares of Stock included within
the Warrant Shares by the percentage increase or decrease in the total number of
shares of Stock outstanding immediately after such event as compared to the
total number of shares of Stock outstanding immediately prior to such event and
the result so obtained shall be the number of Warrant Shares then in effect.

            (b) The Exercise Price and the number of Warrant Shares, as so
adjusted, shall be readjusted in the same manner upon the happening of any
successive event or events described in this Section 4.1

          4.2  ADJUSTMENT FOR REORGANIZATION, CONSOLIDATION OR MERGER.  In the
event that, at any time or from time to time after the Issue Date, the
Corporation shall (a) effect a reorganization, (b) consolidate with or merge
into any other Person, or (c) sell or transfer all or substantially all of its
properties or assets or more than 50% of the voting capital stock of the
Corporation (whether issued and outstanding, newly issued, from treasury, or any
combination thereof) to any other Person under any plan or arrangement
contemplating the reorganization, consolidation or merger, sale or transfer, or
dissolution of the Corporation, then, in each such case, the Holder, upon the
exercise of this Warrant as provided in Section 2 hereof at any time or from
time to time after the consummation of such reorganization, consolidation,
merger or sale or the effective date of such dissolution (subject to the
limitation contained in Section 4.6, if applicable), as the case may be, shall
receive, in lieu of the Warrant Shares issuable on such exercise immediately
prior to such consummation or such effective date, as the case may be, the Stock
and property (including cash) to which the Holder would have been entitled upon

                                      -7-
<PAGE>

the consummation of such reorganization, consolidation or merger, or sale or
transfer, or in connection with such dissolution, as the case may be, if the
Holder had so exercised this Warrant immediately prior thereto (assuming the
payment by the Holder of the Exercise Price therefor as required hereby in a
form permitted hereby, which payment shall be included in the assets of the
Corporation for the purposes of determining the amount available for
distribution), all subject to successive adjustments thereafter from time to
time pursuant to, and in accordance with, the provisions of this Section 4.

          4.3  ADJUSTMENTS FOR RECLASSIFICATIONS.  If the Common Stock issuable
upon the conversion of this Warrant shall be changed into the same or a
different number of shares of any class(es) or series of stock, whether by
reclassification or otherwise (other than an adjustment under Section 4.1 or a
merger, consolidation, or sale of assets provided for under Section 4.2), then
and in each such event, the Holder hereof shall have the right thereafter to
convert each Warrant Share into the kind and amount of shares of stock and other
securities and property receivable upon such reclassification, or other change
by holders of the number of shares of Common Stock into which such Warrant
Shares would have been convertible immediately prior to such reclassification,
or change, all subject to further adjustment as provided herein.

          4.4  DISTRIBUTIONS.  In the event that, at any time or from time to
time after the Issue Date, the Corporation shall make or issue, or shall fix a
record date for the determination of eligible holders entitled to receive, a
dividend or other distribution with respect to Common Stock payable in (i)
shares of its capital stock (other than a stock dividend provided for in Section
4.1), (ii) other securities of the Corporation or any other Person, (iii)
evidences of indebtedness issued by the Company or any other Person, (iv)
options, warrants or rights to subscribe for or purchase any of the foregoing,
or (v) assets (excluding cash dividends) then, in each such case, the Holder of
this Warrant shall receive, in addition to the shares of Stock issuable upon the
exercise of this Warrant prior to such date, and without the payment of
additional consideration therefor, the shares of capital stock, other
securities, evidence of indebtedness, options, warrants or other rights or
assets, as the case may be, to which such Holder would have been entitled upon
such date as if such Holder had exercised this Warrant on the date hereof and
had thereafter, during the period from the date hereof to and including the date
of the actual exercise of this Warrant, retained such shares and/or all other
additional stock available to it as aforesaid during such period, giving effect
to all adjustments pursuant to this Section 4.  The Company shall reserve and
set aside, for the life of this Warrant or until exercised in full, all such
distributions to which the Holder is entitled to receive pursuant to the this
Section 4.4.

          4.5  CONTINUATION OF TERMS.  Upon any reorganization,
reclassification, sale, consolidation, merger or other transfer (and any
liquidation, dissolution or winding up of the Corporation following any such
transfer) referred to in this Section 4, this Warrant shall continue in full
force and effect and the terms hereof shall be applicable to the shares of Stock
and property (including cash, where applicable) receivable upon the

                                      -8-
<PAGE>

exercise of this Warrant after the consummation of such reorganization,
reclassification, sale, consolidation, merger or other transfer or the effective
date of liquidation, dissolution or winding up of the Corporation following any
such transfer, as the case may be, and shall be binding upon the issuer of any
such Stock, including, in the case of any such transfer, the Person acquiring
all or substantially all of the properties or assets or more than 50% of the
voting capital stock of the Corporation (whether issued and outstanding, newly
issued or from treasury or any combination thereof), whether or not such Person
shall have expressly assumed the terms of this Warrant.

          5.  OFFICER'S CERTIFICATE AS TO ADJUSTMENTS.  In each case of any
adjustment or readjustment in the number and kind of Warrant Shares, or
property, issuable hereunder from time to time, or the Exercise Price, the
Corporation, at its expense, will promptly cause an officer of the Corporation
to compute such adjustment or readjustment in accordance with the terms of this
Warrant and prepare a certificate setting forth such adjustment or readjustment
and showing the facts upon which such adjustment or readjustment is based.  The
Corporation will forthwith send a copy of each such certificate to the Holder in
accordance with Section 10.5 below.

          6. NOTICES OF RECORD DATE, ETC. In the event of

          (a) any taking by the Corporation of a record of the holders of Stock
for the purpose of determining the holders thereof who are entitled to receive
any shares of Stock as a dividend or other distribution or pursuant to a stock
split, or

          (b) any reorganization of the Corporation, or any sale or transfer, in
a single transaction or a series of related transactions, of all or
substantially all the assets of the Corporation to, or the consolidation or
merger of the Corporation with or into, any other Person, or

          (c) any voluntary or involuntary dissolution, liquidation or winding-
up of the Corporation, or

          (d) any sale, in a single transaction or a series of related
transactions, of a majority of the Corporation's voting stock (whether newly
issued, or from treasury, or previously issued and then outstanding, or any
combination thereof),

then and in each such event the Corporation will mail or cause to be mailed to
the Holder a notice specifying (i) the date on which any such record is to be
taken for the purpose of such dividend, distribution or stock split, and stating
the amount and character of such dividend, distribution or stock split, or (ii)
the date on which any such reorganization, transfer, consolidation, merger,
dissolution, liquidation or winding-up is to take place, and the time, if any is
to be fixed, as of which the holders of record of any one or more classes of
Stock shall be entitled to exchange their shares of Stock for securities or
other property deliverable on such reorganization, transfer, consolidation,

                                      -9-
<PAGE>

merger, dissolution, liquidation or winding-up, or (iii) the date on which any
such sale of a majority of the Corporation's voting stock is to take place and
the material terms thereof, as the case may be.  Such notice shall be mailed at
least ten (10) days prior to the date specified in such notice on which any such
action is to be taken.

          7.  EXCHANGE OF WARRANT.  Subject to the provisions of Section 9
hereof (if and to the extent applicable), this Warrant shall be exchangeable,
upon the surrender hereof by the Holder at the principal office of the
Corporation, for new warrants of like tenor, each registered in the name of the
Holder or in the name of such other Persons as the Holder may direct.  Each of
such new warrants shall be exercisable for such number of Warrant Shares as the
Holder shall direct, provided that all of such new warrants shall represent, in
the aggregate, the right to purchase the same number of Warrant Shares and cash,
securities or other property, if any, which may be purchased by the Holder upon
exercise of this Warrant at the time of its surrender.

          8.  REPLACEMENT OF WARRANT.  On receipt of evidence reasonably
satisfactory to the Corporation of the loss, theft, destruction or mutilation of
this Warrant and, in the case of any such loss, theft or destruction of this
Warrant, on delivery of a customary affidavit of the Holder and an indemnity
agreement or, in the case of any such mutilation, on surrender and cancellation
of this Warrant, the Corporation at its expense will execute and deliver, in
lieu thereof, a new warrant of like tenor.

          9. TRANSFER PROVISIONS, ETC.

          9.1  LEGENDS.

             (a) Each certificate representing any Warrant Shares issued upon
exercise of this Warrant shall bear the following legend:

        THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933,
     AS AMENDED, AND MAY BE TRANSFERRED ONLY PURSUANT TO AN EFFECTIVE
     REGISTRATION STATEMENT FOR SUCH SECURITIES UNDER THE SECURITIES ACT OF
     1933, AS AMENDED, OR IN ACCORDANCE WITH AN APPLICABLE EXEMPTION FROM THE
     REGISTRATION REQUIREMENTS OF THE SECURITIES ACT OF 1933, AS AMENDED.

             (b) Each certificate representing any shares of Stock issued from
time to time upon exercise of this Warrant shall also bear any legend required
under any applicable state securities or blue sky laws.

        9.2  MECHANICS OF TRANSFER.  Any transfer of all or any portion of this
Warrant, or of any interest therein, that is otherwise in compliance with
applicable law shall be effected by surrendering this Warrant to the Corporation
at its principal office, together with (i) a duly executed form of assignment,
in the form attached hereto, (ii) payment of

                                      -10-
<PAGE>

any applicable transfer taxes, if any. In the event of any such transfer of this
Warrant, in whole, the Corporation shall issue a new warrant of like tenor to
the transferee, representing the right to purchase the same number of Warrant
Shares, and cash, securities or other property, if any, which were purchasable
by the Holder upon exercise of this Warrant at the time of its transfer. In the
event of any such transfer of any portion of this Warrant, (i) the Corporation
shall issue a new warrant of like tenor to the transferee, representing the
right to purchase the same number of Warrant Shares, and cash, securities or
other property, if any, which were purchasable by the Holder upon exercise of
the transferred portion of this Warrant at the time of such transfer, and (ii)
the Corporation shall issue a new warrant of like tenor to the Holder,
representing the right to purchase the number of Warrant Shares, and cash,
securities or other property, if any, purchasable by the Holder upon exercise of
the portion of this Warrant not transferred to such transferee. Until this
Warrant or any portion thereof is transferred on the books of the Corporation,
the Corporation may treat the Holder as the absolute holder of this Warrant and
all right, title and interest therein for all purposes, notwithstanding any
notice to the contrary.

    9.3.  RESTRICTIONS ON TRANSFER.  Subject to compliance with applicable
securities laws and any other contractual restrictions to which the Holder may
be subject, this Warrant, and any portion hereof, and the Warrant Shares may be
transferred by the Holder in its sole discretion at any time to affiliates of
the Holder without the consent of the Corporation.  Except as permitted pursuant
to the foregoing sentence, this warrant may not be transferred without the
consent of the Corporation.

    10.  GENERAL.

    10.1  STATEMENT ON WARRANT.  Irrespective of any adjustments in the Exercise
Price or the number or kind of Warrant Shares, this Warrant may continue to
express the same kind of Warrant Shares as are stated on the front page hereof.

    10.2  AUTHORIZED SHARES; RESERVATION OF SHARES FOR ISSUANCE.  At all times
while this Warrant is outstanding, the Corporation shall maintain its corporate
authority to issue, and shall have authorized and reserved for issuance upon
exercise of this Warrant, such number of shares of Stock as shall be sufficient
to perform its obligations under this Warrant (after giving effect to any and
all adjustments to the number and kind of Warrant Shares purchasable upon
exercise of this Warrant).

    10.3  NO IMPAIRMENT.  The Corporation will not, by amendment of its
Certificate of Incorporation or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issuance or sale of securities, sale or
other transfer of any of its assets or properties, or any other voluntary
action, avoid or seek to avoid the observance or performance of any of the terms
of this Warrant, but will at all times in good faith assist in the carrying out
of all such terms and in the taking of all such action as may be necessary or
appropriate in order to protect the rights of the Holder hereunder against

                                      -11-
<PAGE>

impairment.  Without limiting the generality of the foregoing, the Corporation
(a) will not increase the par value of any shares of Stock receivable upon the
exercise of this Warrant above the amount payable therefor on such exercise, and
(b) will take all action that may be necessary or appropriate in order that the
Corporation may validly and legally issue fully paid and nonassessable shares of
Stock on the exercise of this Warrant.

    10.4  NO RIGHTS AS STOCKHOLDER.  The Holder shall not be entitled to vote or
to receive dividends or to be deemed the holder of Stock that may at any time be
issuable upon exercise of this Warrant for any purpose whatsoever, nor shall
anything contained herein be construed to confer upon the Holder any of the
rights of a stockholder of the Corporation until the Holder shall have exercised
this Warrant and been issued Warrant Shares in accordance with the provisions
hereof.

    10.5  NOTICES.  All notices, demands, requests, certificates or other
communications under this Warrant shall be in writing and shall be either mailed
by certified mail, postage prepaid, in which case such notice, demand, request,
certificate or other communications shall be deemed to have been given three (3)
days after the date on which it is first deposited in the mails, or hand
delivered or sent by facsimile transmission, by tested or otherwise
authenticated telex or cable or by private expedited courier for overnight
delivery with signature required, in each such case, such notice, demand,
request, certificate or other communications being deemed to have been given
upon delivery or receipt, as the case may be:

    (i) if to the Corporation, Prime Response, Inc., 150 Cambridge Park Drive,
Cambridge, MA  02140, Attention: President, or at such other address as the
Corporation may have furnished in writing to the Holder; and

    (ii) if to the Holder, at the Holder's address appearing in the books
maintained by the Corporation.

    10.6  AMENDMENT AND WAIVER.  No failure or delay of the Holder in exercising
any power or right hereunder shall operate as a waiver thereof, nor shall any
single or partial exercise of any such right or power, or any abandonment or
discontinuance of steps to enforce such a right or power, preclude any other or
further exercise thereof or the exercise of any other right or power.  The
rights and remedies of the Holder are cumulative and not exclusive of any rights
or remedies which it would otherwise have.  The provisions of this Warrant may
be amended, modified or waived with (and only with) the written consent of the
Corporation and the Holder.

    10.7  GOVERNING LAW.  This Warrant shall be governed by, and construed and
enforced in accordance with, the laws of the Commonwealth of Massachusetts.

                                      -12-
<PAGE>

    10.8  COVENANTS TO BIND SUCCESSOR AND ASSIGNS.  All covenants, stipulations,
promises and agreements in this Warrant contained by or on behalf of the
Corporation shall bind its successors and assigns, whether so expressed or not.

    10.9  SEVERABILITY.  In case any one or more of the provisions contained in
this Warrant shall be invalid, illegal or unenforceable in any respect, the
validity, legality and enforceability of the remaining provisions contained
herein shall not in any way be affected or impaired thereby.  The parties shall
endeavor in good faith negotiations to replace the invalid, illegal or
unenforceable provisions with valid provisions the economic effect of which
comes as close as possible to that of the invalid, illegal or unenforceable
provisions.

    10.10  CONSTRUCTION.  The definitions of this Warrant shall apply equally to
both the singular and the plural forms of the terms defined.  Wherever the
context may require, any pronoun shall include the corresponding masculine,
feminine and neuter forms.  The section and paragraph headings used herein are
for convenience of reference only, are not part of this Warrant and are not to
affect the construction of or be taken into consideration in interpreting this
Warrant.

    10.11  REMEDIES.  The Holder, in addition to being entitled to exercise all
rights granted by law, including recovery of damages, will be entitled to
specific performance of its rights under this Warrant.  The Corporation agrees
that monetary damages would not be adequate compensation for any loss incurred
by reason of a breach by it of the provisions of this Warrant and hereby agrees
to waive the defense in any action for specific performance that a remedy at law
would be adequate.  In any action or proceeding brought to enforce any provision
of this Warrant or where any provision hereof is validly asserted as a defense,
the successful party to such action or proceeding shall be entitled to recover
reasonable attorneys' fees in addition to any other available remedy.

                    [rest of page intentionally left blank]

                                      -13-
<PAGE>

    IN WITNESS WHEREOF, the Corporation has caused this Common Stock Purchase
Warrant to be executed as an instrument under seal in its corporate name by one
of its officers thereunto duly authorized, all as of the day and year first
above written.

                                         PRIME RESPONSE, INC.
[Corporate Seal]


                                         By: /s/ Frederick H. Phillips
                                            ---------------------------------
                                         Name: Frederick H. Phillips
                                         Title: Secretary, Treasurer,
                                                Senior Vice President and
                                                Chief Financial Officer

                                      -14-
<PAGE>

                              FORM OF SUBSCRIPTION


                   (To be executed upon exercise of Warrant)


To:  PRIME RESPONSE, INC.

    The undersigned hereby irrevocably elects to exercise the right of purchase
represented by the attached Warrant for, and to exercise thereunder, _______
shares of Common Stock, $.01 par value per share ("Common Stock"), of Prime
Response, Inc., a Delaware corporation, and tenders herewith payment of
$__________, representing the aggregate purchase price for such shares based on
the price per share provided for in such Warrant.  Such payment is being made in
accordance with [Section 2.1(b)(i)] [Section 2.1(b)(ii)] [Section 2.1(b)
(iii)] of the attached Warrant.

    Please issue a certificate or certificates for such shares of Common Stock
in the following name or names and denominations and deliver such certificate or
certificates to the person or persons listed below at their respective addresses
set forth below:

Dated:


                         (Address)

    If said number of shares of Common Stock shall not be all the shares of
Common Stock issuable upon exercise of the attached Warrant, a new Warrant is to
be issued in the name of the undersigned for the balance remaining of such
shares of Common Stock less any fraction of a share of Common Stock paid in
cash.


Dated:  ____________, ____
                                        NOTE: The above signature should
                                        correspond exactly with the name on the
                                        face of the attached Warrant or with the
                                        name of the assignee appearing in the
                                        assignment form below.
<PAGE>

                               FORM OF ASSIGNMENT


                  (To be executed upon assignment of Warrant)


    For value received, _____________________________________ hereby sells,
assigns and transfers unto _________________ the attached Warrant [__% of the
attached Warrant], together with all right, title and interest therein, and does
hereby irrevocably constitute and appoint ___________________________ attorney
to transfer said Warrant [said percentage of said Warrant] on the books of Prime
Response, Inc., a Delaware corporation, with full power of substitution in the
premises.

    If not all of the attached Warrant is to be so transferred, a new Warrant is
to be issued in the name of the undersigned for the balance of said Warrant.



Dated:  ____________, ____
                                        NOTE: The above signature should
                                        correspond exactly with the name on the
                                        face of the attached Warrant.