EXHIBIT 99.1

PRESS CONTACTS:

Catherine Taylor               Deidre Moore                  Jim Carini
CMGI Investor Relations        CMGI Public Relations         yesmail.com
978-684-3540                   978-684-3655                  847-918-6379
ctaylor@cmgi.com               dmoore@cmgi.com               jimc@yesmail.com
- ----------------               ---------------               ----------------

                        CMGI COMPLETES ACQUISITION OF
                                  YESMAIL.COM

   PLANS TO LEVERAGE E-MAIL MARKETING LEADER'S 8 MILLION REGISTERED USERS TO
                 IMPROVE MONETIZATION ACROSS THE CMGI NETWORK

ANDOVER, MASS. AND VERNON HILLS, ILL., MARCH 13, 2000 - CMGI, Inc. (Nasdaq:
CMGI) announced today that it has completed its acquisition of yesmail.com
(Nasdaq: YESM), a leading outsourcer of permission email marketing technologies
and services. Under the approved terms of the merger, CMGI will issue .2504
shares of CMGI common stock for every share of yesmail.com common stock held on
March 10, 2000. Effective immediately, yesmail.com becomes a majority-owned
operating company of CMGI, joining CMGI's fast-growing arsenal of interactive
marketing and advertising properties, including Engage (and its subsidiaries
I/PRO and AdKnowledge), Adsmart, AdForce and Flycast.

"When we announced our agreement to acquire yesmail.com three months ago, we
talked extensively about the synergies and benefits the two companies could
bring to one another, and the entire CMGI network. These opportunities are even
bigger today as we begin to more formally integrate yesmail.com's opt-in
marketing services for the benefit of our content and e-commerce companies,
including new, pending acquisitions such as uBid.com," said David Andonian,
president of corporate development for CMGI. "We're excited about the
opportunities ahead and look forward to leveraging yesmail's 8 million
registered users and proven marketing expertise to improve monetization across
the network."

Dave Tolmie, yesmail.com CEO and president added, "We are extremely pleased that
our addition to the CMGI network of companies is complete. We look forward to
working closely with CMGI's leading marketing and advertising companies to
provide the most comprehensive interactive solution available to marketers."

Since the acquisition was announced December 14, 1999, yesmail.com has continued
to experience rapid growth. During the past three months, YesMail membership has
doubled to 8 million and is currently growing by more than 1 million members per
month on average. yesmail.com has also added 32 new Network Partners, including
Egghead.com and TRIP.com, for a current total of 90 YesMail Network Partners.
Collectively, these partners represent 190 individual Web sites.

yesmail.com's revenue for the fourth quarter ended December 31, 1999 was $8.2
million, a 114% sequential increase over the $3.8 million reported for the third
quarter. Total revenue for the year ended December 31, 1999 reached $15.6
million compared with $4.6 million in 1998.

ABOUT YESMAIL.COM
yesmail.com is the premier outsourcer of permission e-mail marketing
technologies and services, providing a total Customer Value Management solution
for its clients - from acquisition to retention and ongoing relationship
management. The YesMail Network(TM) is the Web's first permission-based customer
acquisition and retention engine, enabling YesMail's expert Relationship
Managers to target prospects, personalize messages, deliver campaigns, track and


analyze results, customize responses and generate reports for marketers in real
time. YesMail's proprietary direct marketing software, scalable infrastructure
and experienced strategists deliver a total outsourced solution to maximize
customer value for eMarketers. For more information, contact www.yesmail.com,
1-888-932-8600 or info@yesmail.com.

ABOUT CMGI AND CMGI@VENTURES
With more than 65 companies, CMGI, Inc. (Nasdaq: CMGI) represents the largest,
most diverse network of Internet businesses in the world, including both CMGI
operating companies and synergistic investments made through its venture capital
affiliate, CMGI@Ventures. CMGI leverages the technologies; content and market
reach of its extended family of companies to foster rapid growth and industry
leadership across its network and the larger Internet Economy. Compaq, Intel,
Microsoft, Pacific Century CyberWorks and Sumitomo hold minority positions in
CMGI.

CMGI's majority-owned operating companies include Engage Technologies (Nasdaq:
ENGA), NaviSite (Nasdaq: NAVI), 1ClickBrands, 1stUp.com, Activate.net, AdForce,
Adsmart, AltaVista, CMGI Solutions, Equilibrium, Flycast, iCAST, MyWay.com,
NaviNet, SalesLink, Tribal Voice and yesmail.com. CMGI@Ventures has ownership
interests in 48 Internet companies, including Lycos, Inc. (Nasdaq: LCOS),
Critical Path (Nasdaq: CPTH), Silknet (Nasdaq: SILK), MotherNature.com (Nasdaq:
MTHR), Ventro (Nasdaq: VNTR) and Vicinity (Nasdaq: VCNT). CMGI's corporate
headquarters is at 100 Brickstone Square, Andover, MA 01810, Tel: 978-684-3600.
CMGI@Ventures has offices there as well as at 3000 Alpine Road, Menlo Park, CA
94028. For additional information and a full listing of the CMGI and
CMGI@Ventures companies, see http://www.cmgi.com and http://www.ventures.com.


                                     # # #

This release contains forward-looking statements based on current expectations
or beliefs, as well as a number of assumptions about future events, and these
statements are subject to important factors and uncertainties that could cause
actual results to differ materially from those described in the forward-looking
statements. The forward-looking statements in this release address a variety of
subjects including, for example, the expected benefits resulting from the
acquisition of yesmail.com by CMGI, the expected growth in CMGI's advertising
and marketing business, the expected benefits of yesmail's relationships with
third parties, including AdForce, Flycast, Engage and Adsmart, and the expected
functionality of yesmail's product offerings. The following factors, among
others, could cause actual results to differ materially from those described in
these forward-looking statements: yesmail's business may not be successfully
integrated with the business of CMGI; yesmail's technologies and products may
not successfully interoperate with those of third parties; the adoption of new
laws and regulations affecting the provision of Internet advertising services,
including laws and regulations covering privacy, pricing and content; and
increased competition and technological changes in the industries in which CMGI
and yesmail compete. For a detailed discussion of these and other cautionary
statements, please refer to CMGI's filings with the Securities and Exchange
Commission, including CMGI's Annual Report on Form 10-K for the most recently
ended fiscal year.

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