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                                                                    Exhibit 10.3

April 4, 2001

Mr. Tom Vadnais
30415 Oakview Way
Bingham Farms, MI 48025

Re:  Terms of Employment Offer with Mediaplex, Inc.

Dear Tom:

  Mediaplex, Inc, (the "Company"), is pleased to offer you the position
described below.  This letter sets forth the terms and conditions of your
employment with the Company and is subject to the satisfactory completion of
background and reference checks currently underway.

  I.  Description of Employment Position and Responsibilities.  You will serve
in the position of President and Chief Executive Officer.  At the next regularly
scheduled board meeting you will be appointed to become a member of the
Company's Board of Directors.  By executing this agreement, you agree to assume
and discharge such duties and responsibilities as are commensurate with this
position and such other duties and responsibilities that are assigned to you
from time to time by the Company's Board of Directors.  During the term of your
employment, you shall devote your full time, skill and attention to your duties
and responsibilities and shall perform them faithfully, diligently and
competently.  In addition, you shall comply with and be bound by the operating
policies, procedures and practices of the Company in effect from time to time
during your employment.

  II.  Employment Considerations.

  2.1  At-Will Employment.  You acknowledge that your employment with the
Company is for an unspecified duration that constitutes at-will employment, and
that either you or the Company can terminate this relationship at any time, with
or without cause and with or without notice.

  2.2  Employment Eligibility. Your employment is contingent on your submission
to the Company of satisfactory original documentation to verify your identity
and eligibility for employment in the United States.

  III.  Compensation.

  3.1  Base Salary.  In consideration of your services, effective on your first
day of employment on April 4, 2001, you will be paid an annual base salary of
$400,000 (Four Hundred Thousand Dollars and no Cents), payable no less
frequently than on a monthly basis in accordance with the Company's standard
payroll practices and subject to customary adjustments.  Your base salary, in
conjunction with your performance evaluation, is normally reviewed annually by
the Company's Board of Directors or by the Compensation Committee of the Board.

  3.2  Incentive Compensation.  In addition to your base salary, you will be
eligible for an annual bonus including a 100 percent of salary target with 50
percent guaranteed and paid quarterly, and the remaining 50 percent based on
meeting milestones mutually agreed upon within sixty (60) days of employment by
you and the Company's Board of Directors or the Compensation Committee of the
Board.  These milestones will focus on revenue, profitability, cash in the bank
and stock performance.

  IV.  Additional Benefits.

  4.1  Health Insurance/Vacation/Benefit Plans. You will be entitled to receive
the standard employee benefits made available by the Company to its employees to
the full extent of your eligibility therefor.  You shall be entitled to three
(3) weeks of paid personal time off ("PTO") per year, which may be accumulated
to a maximum of 180 hours; the terms and conditions of your benefits shall be in
accordance with the Company's PTO policy in effect at that time; provided
however, no single vacation shall be in excess of two (2) weeks.  During your
employment, you shall be permitted, to the extent eligible, to participate in
any group medical, dental, life insurance and disability insurance plans, or
similar benefit plan of the Company that is available to employees generally.
Participation in any such plan shall be consistent with your rate of
compensation to the extent that compensation is a determinative factor with
respect to coverage under any such plan.
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  4.2  Reimbursed Expenses.  The Company shall reimburse you for all reasonable
expenses actually incurred or paid by you in the performance of your services on
behalf of the Company, upon prior authorization and approval in accordance with
the Company's expense reimbursement policy as from time to time in effect.  In
addition, the Company shall pay all reasonable out-of-pocket documented expenses
related to relocation moving costs incurred by you, in any event, not to exceed
One Hundred Thousand Dollars ($100,000) (the "Moving Expenses").  The Company
will also pay any taxes that you incur in connection with the Moving Expenses.
Furthermore, the Company will provide you with a monthly automobile allowance of
Seven Hundred and Fifty Dollars ($750.00) and free parking at corporate
premises, or if no such premises exist, then a monthly parking allowance up to a
maximum of Two Hundred and Fifty Dollars ($250.00).

  4.3  Stock Options.  Pursuant to Board approval, and under the terms and
conditions of the Company's Stock Option Plan and Stock Option Agreement,
including the stock vesting provisions contained therein, you will be granted an
option to purchase one million (1,000,000) shares of common stock of the Company
(the "Options").  The Options will vest over four years from date of grant of
April 4, 2001, and at an exercise price equal to the fair market value of the
stock at the date of grant on April 4, 2001.  An additional option to purchase
up to 225,000 shares of common stock of the Company will be granted to you by
the Board (the "Additional Options").  The Additional Options will vest over
four years from the date of grant and at an exercise price equal to the fair
market value of the stock on the date of grant subject to you satisfactorily
meeting certain milestones to be mutually agreed upon within sixty (60) days of
employment with the Company by you and the Board, or the Compensation Committee
of the Board on behalf of the Board.   These milestones shall be the same as
delineated in paragraph 3.2 of this Agreement.

  V.  Termination; Change of Control Benefits.

  5.1  Termination for Other Than Cause.  In the event that the Company elects
to terminate you for other than "Cause" (as defined below), or if you are
"Constructively Terminated" (as defined below), subject to your execution and
non-revocation of a Settlement Agreement and Release satisfactory to the
Company's Board of Directors (the "Release"), the Company will pay to you as
severance, in one lump sum, an amount equal to twelve (12) months of your annual
base salary plus any amounts due and owing to you in effect immediately prior to
the time of such termination.  In addition, you will receive any and all amounts
legally due and owing to you as of the date of termination (e.g., accrued
vacation time and earned bonuses).  Such amount paid will be reduced by all
applicable withholding taxes and other deductions required by law and any
additional amounts authorized by you to be withheld.

  5.2  Voluntary Termination; Cause.  At any time, if your employment is
terminated by the Company with Cause, or if you resign your employment
voluntarily, no compensation or other payments will be paid or provided to you
for periods following the date when such a termination of employment is
effective, provided that any rights you may have under the benefit plans of the
Company shall be determined under the provisions of those plans.  If your
employment terminates as a result of your death or disability, no compensation
or payments will be made to you other than those to which you may otherwise be
entitled under the benefit plans of the Company.

  5.3  Change of Control Compensation.  In the event there should occur a Change
of Control (as defined below), and after such Change of Control, (i) the Company
terminates your employment for any reason other than for Cause (as defined
below) or on account of your permanent disability or death or (ii) there occurs
a Constructive Termination (as defined below), the Company will pay to you as
severance, in one lump sum amount (unless you indicate in writing to the Company
prior to the Company's payment of your election to be paid in installments over
a specified period) an amount equal to twelve (12) months of your annual base
salary plus any amounts due and owing to you in effect immediately prior to the
time of such termination.  Such amounts paid will be reduced by all applicable
withholding taxes and other deductions required by law and any additional
amounts authorized by you to be withheld.

  Termination Not For Cause Or Constructive Termination:  Acceleration Of
Options.  In the event, a Change of Control should occur, and after such Change
of Control, the Company terminates your employment without Cause or if you are
"Constructively Terminated" (as defined below), then subject to your execution
and non-revocation of
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the Release, the vesting of one hundred (100) percent of your Options shall be
accelerated such that one hundred (100) percent of your Options will be
immediately exercisable.

  5.4  Other Change of Control Benefits.  Subject to your execution and non-
revocation of the Release, in addition to any amounts payable under Section 5.3
above, for a period of twelve (12) months following termination of employment,
the Company will continue to provide you with, and pay the same portion of the
cost as is then paid by the Company as of the termination date of health,
disability and life insurance coverage for you, your spouse and dependents that
is commensurate with the coverage then provided to you at the time of
termination, provided that you timely elect to continue your (and if applicable,
your dependants') coverage under COBRA and do not receive coverage under a
comparable plan from another employer.  The Company will structure such health,
disability and life insurance coverage as nontaxable benefits to the maximum
extent possible, including, but not limited to, by characterizing such benefits
as coverage to a former employee.  Specifically for health insurance coverage to
the extent permitted by the Consolidated Omnibus Budget Reconciliation Act of
1985 ("COBRA") and by the Company's group health insurance policies, you will
elect COBRA continuation coverage and the Company will pay you and your covered
dependents' COBRA continuation premiums for twelve months (12) following the
date of termination of employment. You agree to notify the Vice President of
Human Resources of the Company in writing immediately upon the commencement of
health benefit coverage, which would cause your COBRA continuation coverage to
cease.  This Section 5.4 provides only for the Company's payment of COBRA
continuation premiums for the periods specified above.  This Section V is not
intended to affect, nor does it affect, the rights of you, or your covered
dependents under any applicable law with respect to health insurance
continuation coverage.

  5.5  Outplacement Services.  Subject to your execution and non-revocation of
the Release, in addition, the Company will, at its sole expense as incurred, for
a period of twelve (12) months following termination of employment, provide you
with outplacement services the scope and provider of which will be selected by
you in your sole discretion.

  5.6  Change in Control Definitions.  For purposes of this Agreement:

  (a) A "Change in Control" will be deemed to occur upon consummation of any one
of the following:

         (i)    a sale, lease or other disposition of all or substantially all
      of the assets of the Company;

         (ii)   a merger, consolidation or other reorganization in which the
      Company is not the surviving corporation and the stockholders of the
      Company immediately prior to the merger, consolidation or other
      reorganization fail to possess direct or indirect ownership of more than
      fifty percent (50%) of the voting power of the securities of the surviving
      corporation (or if the surviving corporation is a controlled affiliate of
      another Person, then the required beneficial ownership will be determined
      with respect to the securities of that Person which controls the surviving
      corporation and is not itself a controlled affiliate of any other Person)
      immediately following such transaction;

         (iii)  a merger, consolidation or other reorganization in which the
      Company is the surviving corporation and the stockholders of the Company
      immediately prior to such merger, consolidation or other reorganization
      fail to possess direct or indirect beneficial ownership of more than fifty
      percent (50%) of the securities of the Company (or if the Company is a
      controlled affiliate of another Person, then the required beneficial
      ownership will be determined with respect to the securities of that Person
      which controls the Company and is not itself a controlled affiliate of any
      other Person) immediately following such transaction;

         (iv)   any transaction or series of related transactions after which
      any person (as such term is defined in Section 13(d)(3) of the Securities
      Exchange Act of 1934, as amended (the "Exchange Act")), other than any
      employee benefit plan or related trust sponsored or maintained by the
      Company or any subsidiary of the Company, becomes the beneficial owner
      (within the meaning of Rule 13d-3 under the Exchange Act or comparable
      successor rule) of voting securities of the Company representing thirty
      percent (30%) or more of the combined voting power of all of the voting
      securities of the Company;

         (v)    the individuals who, as of the date immediately following the
      Company's 2000 Annual Meeting of Stockholders, are members of the
      Company's Board of Directors (the "Incumbent Board")

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      cease for any reason to constitute at least fifty percent (50%) thereof.
      (If the election, or nomination for election by the Company's
      stockholders, of any new director was approved by a vote of at least two-
      thirds (2/3) of the Incumbent Board, such new director will be considered
      as a member of the Incumbent Board); and

         (vi) the liquidation or dissolution of the Company.

  For purposes of Sections 5.6(a)(ii) and 5.6(a)(iii) above, any Person who
acquired securities of the Company prior to the occurrence of the specified
transaction in contemplation of such transaction and who immediately after such
transaction possesses direct or indirect beneficial ownership of at least ten
percent (10%) of the securities of the Company or the surviving corporation, as
appropriate (or if the Company or the surviving corporation is a controlled
affiliate, then of the appropriate Person as determined above), will not be
included in the group of stockholders of the Company immediately prior to such
transaction.

  (b) A "Constructive Termination" means any of the following:

         (i)    a reduction, without your written consent, in your then current
      annual base salary (other than any base salary reduction that is
      implemented generally with respect to all executives at the Company); or

         (ii)   a reduction in your position and/or responsibilities as Chief
      Executive Officer; and

         (iii)  a relocation of your principal place of employment by more than
      seventy (70) miles, unless you consent in writing to such relocation; and

  (c) " Cause" shall mean any one of the following: (i) your conviction (or plea
of guilty or nolo contendere to) of a felony, or committing an act of
dishonesty, fraud or the misappropriation of Company property, (ii) your willful
engagement in gross misconduct or willful neglect which are significantly and
demonstrably injurious to the Company, (iii) your failure or refusal to perform
duties of your position, such as a directive from the Company's Board of
Directors which failure or refusal is not cured within fifteen (15) days after
you are notified in writing of the specific failure or refusal, (iv) your breach
in any material respect the terms of this Agreement or the Intellectual Property
Agreement (attached); or (v) your commencement of employment with another
employer while you are employed by the Company.

  (d) "Person" means an individual, corporation, partnership, limited liability
company, association, trust, unincorporated organization or other legal entity
including any governmental entity.

  VI.  Continuation of Employment and Cooperation with the Company after Change
in Control. Following a Change in Control, you agree that you will continue to
provide your services as an employee of the Company (or the successor to the
Company), as requested, as previously provided prior to the Change in Control or
such performance as is reasonably requested by the Company (or its successor)
and is substantially similar as your duties prior to such Change in Control; and
to cooperate with the Company (or its successor) in all matters relating to any
winding up of your pending work on behalf of the Company (or its successor) and
the orderly transfer of any such pending work to other employees of the Company
(or its successor) as may be designated by the Company (or its successor), which
period will not exceed ninety (90) days.  Furthermore, you agree to return all
property of the Company in your possession or control to the Company (or its
successor) as promptly as practicable within ten (10) days after the effective
date of your termination of employment, except to the extent that retention of
any of such property is necessary or desirable or convenient in order to permit
you to satisfy your obligations under this Section VI.  The performance of your
obligations under this Section VI shall be a condition to any and all of the
benefits payable or otherwise granted to you upon a termination of your
employment after a Change in Control pursuant to Section VI hereof.

  VII.  Intellectual Property Rights/Confidential Information.

  7.1  Valuable Trade Secrets.  You agree that the Company is the owner of
valuable trade secrets, client, vendor, customer and contractor lists and other
confidential and proprietary information.  As such, you agree that

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your employment is contingent upon your execution of, and delivery to, the
Company of a Confidential Information and Invention Assignment Agreement
("Intellectual Property Agreement") in the standard form utilized by the
Company.

  7.2  Additional Confidential Information.  You agree to maintain the
confidentiality of all elements of this Agreement, agreeing to an absolute
prohibition on any disclosure or use of such information in any fashion, with
the exception of discussions with the Company's Human Resources Department,
Legal Department or Board of Directors or any agents acting on behalf of the
Board. As you are well aware, the maintenance of confidentiality of this kind of
information is critical to our organization.

  7.3  Equitable Remedies.  You agree that it would be impossible or inadequate
to measure and calculate the Company's damages from any breach of the covenants
set forth in this Section as well as Sections 1, 2, 3, and 5 of the Intellectual
Property Agreement.  Accordingly, you agree that if you breach any of such
Sections, the Company will have available, in addition to any other right or
remedy available, the right to obtain an injunction from a court of competent
jurisdiction restraining such breach or threatened breach and to specific
performance of any such provision of this Agreement.  You further agree that no
bond or other security shall be required in obtaining, such equitable relief and
you hereby consent to the issuance of such injunction and to the ordering of
specific performance.

  VIII.  Non-Competition/Conflicting Employment.  You agree that, during the
term of your employment with the Company, you will not engage in any other
employment, occupation, consulting or other business activity directly related
to the business in which the Company and/or its customers are now involved or
become involved during the term of your employment, nor will you engage in any
other activities that conflict with your obligations to the Company.

  IX.  Arbitration.  Except as otherwise provided in Section 7.3 above, it is
agreed that any dispute or controversy arising out of or relating to any
interpretation, construction, performance or breach of this Agreement, shall be
exclusively settled by confidential arbitration to be held in San Francisco
County, California, in accordance with the rules then in effect of the American
Arbitration Association.  The arbitrator may grant injunctions or other relief
in such dispute or controversy.  The decision of the arbitrator shall be final,
conclusive and binding on the parties to the arbitration.  Judgement may be
entered on the arbitrator's decision in any court having jurisdiction.  Each
party shall pay one-half of the costs and expenses of such arbitration, and each
of us shall separately pay our counsel fees and expenses.

  X.  General Provisions.

  10.1  Governing Law.  This offer letter will be governed by the laws of the
State of California.

  10.2  Entire Agreement.  This offer letter sets forth the entire agreement and
understanding between the Company and you relating to your employment and
supersedes all prior verbal discussion and written agreements between us.  Any
subsequent change or changes in your duties, salary or other compensation will
not affect the validity or scope of this agreement.  Any change to the at-will
term of this agreement must be executed in writing and signed by you and the
Board, or the Compensation Committee of the Board on behalf of the Board.

  10.3  Successors/Assigns.  This agreement will be binding upon your heirs,
executors, administrators and other legal representatives and will be for the
benefit of the Company and its respective successors and assigns.

  Please acknowledge and confirm your acceptance of this letter by signing and
returning the enclosed copy of this offer letter, and the Confidential
Information and Invention Assignment Agreement as soon as possible.

  If you have any questions about this offer letter, please call me directly.

  MEDIAPLEX, INC.

                                 By:       /s/ Gregory R. Raifman
                                     ------------------------------------
                                     Gregory R. Raifman
                                     Chairman and Chief Executive Officer
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  ACCEPTANCE:

  I accept the terms of my employment with Mediaplex, Inc. as set forth herein.
I understand that this offer letter does not constitute a contract of employment
for any specified period of time, and that my employment relationship may be
terminated by either party, with or without cause and with or without notice.


  ACCEPTED AND AGREED:

      /s/ Tom A. Vadnais          Date:    4/4/01
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  Tom A.Vadnais