<PAGE>

                                                                    Exhibit 10.2

                           ART TECHNOLOGY GROUP, INC.
                   2005 EXECUTIVE MANAGEMENT COMPENSATION PLAN

      The executive officers of ATG are eligible to participate in this plan,
subject to the execution by the executive officer of the Terms and Conditions of
Participation set forth as Exhibit A to this plan. The target bonus payout for
the indicated periods and the applicable performance metrics for each executive
officer are as follows:

<TABLE>
<CAPTION>
                                    TARGET BONUS
                                       PAYOUT
                                    (AT 100% OF
                                    PERFORMANCE
       TITLE           PERIOD         METRICS)            PERFORMANCE METRICS
-------------------   ---------   ----------------   ------------------------------
<S>                   <C>         <C>                <C>
CEO                   Annual*     $ 175,000          40% ATG Operating Profit**
                                                     40% ATG Revenue
                                                     20% MBOs

CFO                   Annual*     $ 100,000          50% ATG Operating Profit**
                                                     30% ATG Revenue
                                                     20% Cash Mgmt

SVP SALES             Annual*     $ 40,000           100% ATG Operating Profit**

                      Quarterly   $ 40,000/quarter   90% ATG Revenue
                                 ($160,000/year)     10% CSS Renewals

SVP MARKETING         Annual*     $ 100,000          30% ATG Operating Profit**
                                                     40% ATG Revenue
                                                     30% Marketing Initiatives

SVP HUMAN RESOURCES   Annual*     $ 80,000           40% ATG Operating Profit**
                                                     20% ATG Revenue
                                                     25% HR Initiatives/MBOs
                                                     15% Employee Satisfaction

SVP PRODUCTS &        Annual*     $ 88,000           30% ATG Operating Profit**
TECHNOLOGY                                           30% ATG Revenue
                                                     30% Product Initiatives/MBOs
                                                     10% Customer Satisfaction
</TABLE>

* No bonus will be paid for the annual period unless ATG achieves, at minimum,
50% of its operating profit goal for 2005.

** In measuring the ATG operating profit, restructuring charges are excluded but
amortization is included.

<PAGE>

                                                                       EXHIBIT A

                      TERMS AND CONDITIONS OF PARTICIPATION
                 ATG 2005 EXECUTIVE MANAGEMENT COMPENSATION PLAN

1.    No incentive payments will be paid unless you are actively employed by ATG
      at the time incentive payments are made, or unless otherwise provided in a
      separate written agreement between you and ATG. Payments are generally
      made six to twelve weeks following the end of the applicable period if
      approved financial statements are available.

2.    These payments are offered as an incentive, but are not guaranteed. ATG
      (including the Compensation Committee of ATG's Board of Directors)
      reserves the sole right to make changes to any and all terms and
      conditions of the 2005 Executive Management Compensation Plan due to
      changes in business conditions, performance of the executive or the
      company or other factors, at the sole discretion of the Compensation
      Committee of ATG's Board of Directors.

3.    ATG reserves the right to make goal substitutions to meet changing
      business requirements. There may be additional deliverables not explicitly
      detailed in the attached MBO listing, as specified by ATG Management.

4.    Participation in the 2005 Executive Management Compensation Plan is no
      guarantee of participation in any subsequent plans. The company reserves
      the sole right to designate participants, and to make any and all changes
      to a participant's yearly plan.

5.    The final payout amount must be approved by the Compensation Committee of
      ATG's Board of Directors, including payout of any amounts over 100% of
      target and partial payments when targets are partially achieved.
      Additional factors may be considered in determining the final payout
      amount.

6.    In all circumstances, the amount and timing of any incentive payment are
      solely within the discretion of the Compensation Committee of ATG's Board
      of Directors, regardless of the provisions of the 2005 Executive
      Management Compensation Plan.

Agreed by:

________________________________________________________________________________
Executive Signature                                        Date

________________________________________________________________________________
CEO Signature                                              Date