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                                                                   EXHIBIT 10.17

As of November 1, 2002

Christopher Saridakis
DoubleClick Inc.
450 W. 33rd Street
New York, NY 10001

Dear Chris:

    This letter agreement will confirm our understandings and obligations in
connection with your separation from DoubleClick Inc. As used in this letter
agreement, 'DoubleClick' is defined to include, as appropriate, DoubleClick
Inc., any directly or indirectly held subsidiary, any affiliated entity, and any
successor to any of the foregoing.

    Resignation. You hereby resign, effective immediately, from your position as
Senior Vice President, Global TechSolutions and any other currently held
positions with DoubleClick. This letter agreement confirms that your authority
and responsibility for any DoubleClick 'policymaking function' (as that term is
used in Rule 16a-1 to the Rules and Regulations to the Securities Exchange Act
of 1934) immediately ceases upon your resignation from these positions. From
today through and including the earlier of May 30, 2003, or the date upon which
you obtain new employment, which date will be the effective date of your
termination (the 'Termination Date'), you will continue to be employed by
DoubleClick and will assist in those special projects as may be designated by
DoubleClick's Chief Executive Officer or President and reasonably acceptable to
you. DoubleClick acknowledges that you will be able to serve in your new
capacity without being present in DoubleClick's offices on a daily basis.

    Separation Pay. In lieu of a notice period and in consideration for your
agreeing to the terms of this agreement, you will receive: (a) your regular
salary at your current base rate of pay for the period from today through and
including May 30, 2003, with any then-unpaid balance to be paid in a lump sum in
the event of any Termination Date that occurs before May 30, 2003; and (b) a
lump-sum payment of $93,333.33, based on target commissions for the fourth
quarter 2002 ($53,333.33) and first quarter 2003 ($40,000), payable on or about
the earlier of the Termination Date, or the conclusion of each respective
quarter in the ordinary course of business. All payments will be less customary
deductions and withholdings.

    You agree to notify me in writing upon acceptance of employment with any
other employer.

    Stock Sales. DoubleClick will, to the extent necessary, file to remove you
as a Section 16 reporting officer. You acknowledge that you are familiar with
the trading and reporting requirements applicable to a former Section 16
reporting officer. Until May 1, 2003, you agree to continue to abide by
DoubleClick's insider trading policies, for which purposes you shall remain a
'Listed Employee' until November 1, 2002. During the period until May 1, 2003,
you agree to notify DoubleClick in advance of any planned stock sales by you, a
member of your household or those financially dependent on you, although it is
acknowledged that you will no longer be subject to DoubleClick's insider trading
policies following the Termination Date.

    Stock Options. This letter agreement confirms that all stock options granted
to you by DoubleClick prior to the date of this letter will continue to vest
according to their respective terms through and including the Termination Date.

    Release of Claims. You, on your own behalf and on behalf of any spouse,
heirs, legal representatives, successors-in-interest, and assigns, waive,
release, and discharge DoubleClick Inc., its present and former subsidiaries,
divisions, departments, affiliated entities, predecessors, partners, joint
venturers, directors, officers, shareholders, agents, employees, successors, and
assigns from any and all claims, rights, demands, debts, obligations, damages or
accountings of whatever nature which you may have, may have had, or, in the
future, may believe you had, against DoubleClick occurring prior to the




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date of this agreement, whether known or unknown, asserted or unasserted,
including but not limited to: (a) all claims and liability for any acts that
violated or may have violated your rights under any contract, tort, or other
common law, any federal, state, or local fair employment practices or civil
rights law or regulation, any employee relations statute, executive order, law,
regulation, or ordinance, any workers compensation law, or any other duty or
obligation of any kind, including but not limited to rights created by 42 U.S.C.
'SS' 1981, Title VII of the Civil Rights Act of 1964 ('Title VII'), the Age
Discrimination in Employment Act ('ADEA'), the Americans with Disabilities Act
('ADA'), the Family and Medical Leave Act ('FMLA'), and all other federal,
state, and local laws prohibiting employment discrimination of whatever kind or
nature; (b) all liability for any claims whatsoever which were or may have been
alleged against or imputed to DoubleClick by you or anyone acting on your
behalf; (c) all rights to or claims for wages, commissions, monetary or
equitable relief, or compensatory, punitive, or liquidated damages, or
reemployment or reinstatement in any position; and (d) all rights to or claims
for attorneys' fees, costs, or disbursements.

    DoubleClick, on its own behalf and on behalf of any present and former
subsidiaries, divisions, departments, affiliated entities, predecessors,
partners, joint venturers, directors, officers, shareholders, agents, employees,
successors, and assigns waives, releases, and discharges you, your spouse,
heirs, legal representatives, and assigns, from any and all claims, rights,
demands, debts, obligations, damages, or accountings of whatever nature which it
may have, may have had, or, in the future, may believe it had, against you
arising prior to the date of its signing this agreement, whether known or
unknown, asserted or unasserted other than acts or conduct constituting fraud,
gross negligence, or willful misconduct.

    On or promptly following the Termination Date, DoubleClick hereby agrees to
execute a release in the form attached hereto as Exhibit A, and you hereby agree
to execute a release in the form attached hereto as Exhibit B. You acknowledge
and agree that DoubleClick's obligation to pay any Separation Pay to you
hereunder (other than salary continuation) is expressly contingent upon your
execution of the release attached as Exhibit B (provided that DoubleClick
concurrently executes the release attached as Exhibit A).

    Confidentiality. You shall keep the terms and conditions of this agreement
strictly confidential. You shall not disclose the terms of this agreement,
except to your tax, finance, or legal advisors, or to your immediate family
members, or to potential new employers, each of whom will also have an
obligation of confidentiality.

    You further recognize and reaffirm that the Employee Covenant of
Confidentiality and the Employee Proprietary Information and Inventions
Agreement you signed pursuant to your employment with DoubleClick continue in
full force and effect. You agree that you will never disclose DoubleClick trade
secret or proprietary information, including but not limited to information in
its databases, technical or scientific information relating to current or future
products, services, or research, business or marketing plans or projections,
earnings and other financial data, personnel information, including executive
and organizational changes, software, computer systems, and programs, and
policies and procedures of DoubleClick.

    Return of Company Property. By signing below, you agree that you will return
to DoubleClick, on or before the Termination Date, any documents (including
electronic documents, disks, and files) that you received and/or created as part
of your employment with DoubleClick and that remain in your possession, custody,
or control, and you further agree that you will not, to the best of your
knowledge and belief, have retained (yourself or through an agent) any copies
thereof. You further agree that you will, on or before the Termination Date, all
tangible company property that remains in your possession, custody, or control,
including but not limited to company-sponsored credit cards and/or calling
cards, cellular telephones, computer equipment, keys, badges, and any other
company property. You agree and understand that your material compliance with
the requirements of this paragraph is an express condition to your entitlement
to the Separation Pay set forth above. We acknowledge that you will vacate your
office following the date of this letter agreement, and that you may remove your
personal belongings from the company premises at your convenience. You agree
that DoubleClick may, at its discretion, examine all documents and other
materials that you have designated as personal, prior to their removal from the
company premises. Through and including the Termination Date, you will be
allowed continued use of your computer, email account, and DoubleClick telephone
number.

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    Non-Solicitation. You agree that for the duration of your employment with
DoubleClick and through and including April 30, 2004 (the 'Restricted Period'),
you may not solicit any DoubleClick employee on behalf of another employer or
encourage any DoubleClick employee to leave the company. Similarly, you agree
that for the same period of continued employment and through and including the
Restricted Period, you may not solicit any DoubleClick account, on your behalf
or on behalf of any other individual or entity, for the purpose of engaging in
'DoubleClick Competitive Business' (as defined in the following paragraph).

    Non-Competition. You agree that for the duration of your employment with
DoubleClick and through and including the Restricted Period, you may not, as an
employee, agent, consultant, advisor, independent contractor, partner, officer,
director, stockholder, owner, co-venturer, principal, investor, lender, or
guarantor of any corporation, partnership, or other entity, or in any other
capacity, directly or indirectly: (a) engage in any business in which
DoubleClick, as of the Termination Date, is engaged or, to your knowledge,
proposes to engage, in each case a material part of DoubleClick's business
('DoubleClick Competitive Business'); (b) authorize your name to be used in
connection with a DoubleClick Competitive Business; or (c) acquire any debt,
equity, or other ownership interest in any person or entity engaged, to your
knowledge, in a DoubleClick Competitive Business, except that you may own, in
the aggregate, not more than one percent (1%) of the outstanding equity of any
publicly traded entity that is engaged in a DoubleClick Competitive Business as
a material part of such entity's business. You hereby acknowledge that the scope
of this non-competition obligation is fair and reasonable, and is given in
consideration of the other benefits set forth in this letter agreement.

    Duty to Cooperate. You agree to cooperate with DoubleClick in providing
truthful testimony or information with respect to all inquiries or
investigations, claims and litigation pertaining to DoubleClick.

    Benefits. You are entitled to the following benefits: You will receive
payment for any accrued but unused Paid Time Off days through November 1, 2002.
You will receive any entitlement under DoubleClick's 401(k) plan in accordance
with the terms of the plan as applied to all covered employees. You will be
refunded the post-tax value of your cash balance from contributions, if any, to
the Employee Stock Purchase Plan. You will be reimbursed for any usual and
ordinary business expenses incurred in connection with your employment in
accordance with DoubleClick's expense policy. You will be entitled to retain,
and exercise, all stock options vested on or before the Termination Date in
accordance with the terms expressed in the respective notices of grant of stock
option. Your entitlement to stock option vesting shall cease completely as of
that date.

    Your benefits and coverages under the medical insurance arrangements to
which you are subject as of the date of this agreement will continue, under the
current terms and conditions, through the last day of the month in which your
Termination Date falls, on which date such benefits and coverages will cease and
you will be eligible to continue such benefits and coverages at your expense
pursuant to the federal law known as COBRA. You will be receiving more detailed
information concerning your option to continue your health coverage under
separate cover. Other than the foregoing benefits and the Separation Pay set
forth above, you will not be entitled to any form of payment or benefit.

    Entire Agreement/Choice of Law/Severability. This agreement contains the
entire agreement between the parties and shall be governed by the laws of the
State of New York without giving effect to its principles of conflicts of law.
You hereby agree that you are subject to the jurisdiction of the courts of the
State of New York. This agreement may not be changed orally, but only by an
agreement in writing signed by the party against whom enforcement of any waiver,
change, modification or discharge is sought.

    Should any provision of this agreement be declared or be determined by any
court of competent jurisdiction to be illegal or invalid, the validity of the
remaining parts, terms, or provisions shall not be affected thereby and said
illegal or invalid part, term, or provision shall be deemed not to be part of
this agreement.

    Acknowledgment. You acknowledge by signing this agreement that you have read
it in its entirety, understand all of its terms and conditions, and knowingly
and voluntarily assent to those terms and conditions. Any alterations to this
agreement shall not affect its terms; your signature shall be deemed

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an acceptance of its terms without modification. You further acknowledge that
you have been advised of your right to consult with counsel in connection with
this agreement.

    To signify your acceptance of these terms, please sign and date this
agreement in the space provided and return the original to me within seven days.

    We wish you the best of success in your future endeavors.

                                          Very truly yours,

                                          DOUBLECLICK INC.

                                          BY:         /s/ MELANIE HUGHES
                                              ..................................
                                                       MELANIE HUGHES
                                                    SVP, HUMAN RESOURCES

AGREED TO AND ACCEPTED:

BY:      /s/ CHRISTOPHER SARIDAKIS
     .................................
          CHRISTOPHER SARIDAKIS

           November 1, 2002
 .....................................
                 DATE

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                                                                       EXHIBIT A

                     RELEASE OF CLAIMS BY DOUBLECLICK INC.

    For good and valuable consideration, DoubleClick Inc., on its own behalf and
on behalf of any present and former subsidiaries, divisions, departments,
affiliated entities, predecessors, partners, joint venturers, directors,
officers, shareholders, agents, employees, successors, and assigns (collectively
referred to hereinafter as 'DoubleClick') waives, releases, and discharges
Christopher Saridakis, any spouse, heirs, legal representatives, and assigns
(collectively, 'Saridakis'), from any and all claims, rights, demands, debts,
obligations, damages or accountings of whatever nature which it may have, may
have had, or, in the future, may believe it had, against Saridakis arising prior
to the date of its signing this release, whether known or unknown, asserted or
unasserted other than acts or conduct constituting fraud or intentional
misconduct, including but not limited to: (a) all claims and liability for any
acts that violated or may have violated its rights under any contract, tort, or
other common law, any federal, state or local law, or any other duty or
obligation of any kind; (b) all liability for any claims whatsoever which were
or may have been alleged against or imputed to Saridakis by DoubleClick or
anyone acting on Saridakis' behalf; (c) all rights to or claims for wages,
commissions, monetary or equitable relief, or compensatory, punitive, or
liquidated damages, or reemployment or reinstatement in any position; and
(d) all rights to or claims for attorneys' fees, costs, or disbursements.

    Notwithstanding the foregoing, this release shall not apply to claims based
on, or preserved by, the November 1, 2002 letter agreement between Saridakis and
DoubleClick.

                                          DOUBLECLICK INC.

                                          BY:
                                              ..................................
                                                       MELANIE HUGHES
                                                    SVP, HUMAN RESOURCES

                                          Dated:  ..............................

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                                                                       EXHIBIT B

                   RELEASE OF CLAIMS BY CHRISTOPHER SARIDAKIS

    For good and valuable consideration, I, on my own behalf and on behalf of
any spouse, heirs, legal representatives, and assigns, waive, release, and
discharge DoubleClick Inc., its present and former subsidiaries, divisions,
departments, affiliated entities, predecessors, partners, joint venturers,
directors, officers, shareholders, agents, employees, successors, and assigns
(collectively referred to hereinafter as 'DoubleClick') from any and all claims,
rights, demands, debts, obligations, damages, or accountings of whatever nature
which I may have, may have had, or, in the future, may believe I had, against
DoubleClick arising prior to the date of my signing this release, whether known
or unknown, asserted or unasserted, other than acts or conduct constituting
fraud or intentional misconduct, including but not limited to: (a) all claims
and liability for any acts that violated or may have violated my rights under
any contract, tort, or other common law, any federal, state, or local fair
employment practices or civil rights law or regulation, any employee relations
statute, executive order, law, regulation, or ordinance, any workers
compensation law, or any other duty or obligation of any kind, including but not
limited to rights created by 42 U.S.C. 'SS' 1981, Title VII of the Civil Rights
Act of 1964 ('Title VII'), the Age Discrimination in Employment Act ('ADEA'),
the Americans with Disabilities Act ('ADA'), the Family and Medical Leave Act
('FMLA'), and all other federal, state, and local laws prohibiting employment
discrimination of whatever kind or nature; (b) all liability for any claims
whatsoever which were or may have been alleged against or imputed to DoubleClick
by me or anyone acting on my behalf; (c) all rights to or claims for wages,
commissions, monetary, or equitable relief, or compensatory, punitive, or
liquidated damages, or reemployment or reinstatement in any position; and
(d) all rights to or claims for attorneys' fees, costs, or disbursements.

    Notwithstanding the foregoing, this release shall not apply to claims based
on, or preserved by, the November 1, 2002 letter agreement between me and
DoubleClick.

                                           .....................................
                                                  CHRISTOPHER SARIDAKIS

                                          Dated:  ..............................

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