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Exhibit 5.1
August 22, 2000
Mediaplex, Inc.
177 Steuart Street, Second Floor
San Francisco, California 94105-1230
Re: Registration Statement on Form S-8
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Ladies and Gentlemen:
We have examined the Registration Statement on Form S-8 to be filed by you
with the Securities and Exchange Commission on or about August 23, 2000 (the
"Registration Statement") in connection with the registration under the
Securities Act of 1933, as amended (the "Securities Act"), of 2,300,000
additional shares of your Common Stock reserved for issuance under (i) the
Amended and Restated 1999 Stock Plan (the "1999 Plan"), (ii) the 1999 Employee
Stock Purchase Plan (together, with the 1999 Plan, the "Plans") and (iii) the
Internet Extra Corporation Warrant Purchase Agreement and related Common Stock
Purchase Warrant (together, with the 1999 Plan the "Warrant"). As your legal
counsel, we have examined the proceedings taken and are familiar with the
proceedings proposed to be taken by you in connection with the sale and
issuance of such Common Stock under the Plans and the Warrant.
It is our opinion that, when issued and sold in the manner referred to in
the Plans and the Warrant and pursuant to the agreements that accompany the
Plans and the Warrant, the Common Stock issued and sold thereby will be
legally and validly issued, fully paid and non-assessable.
We consent to the use of this opinion as an exhibit to the Registration
Statement, and further consent to the use of our name wherever appearing in the
Registration Statement, including any Prospectuses constituting a part thereof,
and any amendments thereto. This opinion may be incorporated by reference in any
abbreviated registration statement filed pursuant to Item E under the General
Instructions to Form S-8 under the Securities Act with respect to the
Registration Statement.
Very truly yours,
WILSON SONSINI GOODRICH & ROSATI
Professional Corporation
/s/ Wilson Sonsini Goodrich & Rosati
