content: <PAGE>
  
                       SECURITIES AND EXCHANGE COMMISSION
  
                             WASHINGTON, D.C. 20549
  
                                    FORM 8-K
  
                                 CURRENT REPORT
  
     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
  
     Date of Report (Date of earliest event reported):  September 29, 1999.
  
                       FLYCAST COMMUNICATIONS CORPORATION
             (Exact name of registrant as specified in its charter)
  
            DELAWARE                   00025467                   77-0431028
        (State or other          (Commission File Number)       (IRS Employer
  jurisdiction of incorporation)                             Identification No.)
  
  
                               181 FREMONT STREET
                        SAN FRANCISCO, CALIFORNIA  94105
                     --------------------------------------
                     Address of principal executive offices
  
                                 (415) 977-1000
                     --------------------------------------
               Registrant's telephone number, including area code
  
  --------------------------------------------------------------------------------
  <PAGE>
  
  ITEM 2.  ACQUISITION OR DISPOSITION OF ASSETS
  
       On September 29, 1999, CMGI, Inc., a Delaware corporation ("CMGI"), agreed
  to acquire Flycast Communications Corporation, a Delaware corporation
  ("Flycast"), through a merger of Fremont Corporation, a Delaware corporation and
  a wholly owned subsidiary of CMGI (the "Transitory Subsidiary") with and into
  Flycast, as a result of which the stockholders of Flycast will become
  stockholders of CMGI.  Under the terms of the agreement, CMGI will issue .4738
  shares for every share of Flycast held on the closing date of the transaction.
  The close of the merger, expected in January 2000, is subject to customary
  conditions, including formal approval by Flycast stockholders.  A copy of the
  Agreement and Plan of Merger, by and among CMGI, Flycast and Transitory
  Subsidiary, dated September 29, 1999, is attached hereto as Exhibit 2.1.
  
       In connection with the merger, CMGI and Flycast also entered into a Stock
  Option Agreement, whereby Flycast granted CMGI an option to purchase up to
  3,036,750 shares of common stock at a cash purchase price equal to $47.53 per
  share; provided, however, that the number of shares issuable to CMGI shall not
  exceed 19.9% of the outstanding shares of Flycast common stock.  The option may
  be exercised by CMGI in the event that the merger is terminated under certain
  circumstances.  A copy of the Stock Option Agreement, by and among CMGI and
  Flycast, dated September 29, 1999, is attached hereto as Exhibit 2.2.
  
  ITEM 7.  FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS
  
           (a) It is impracticable for the registrant to provide the required
               financial statements for the business acquired at the time of
               filing this report, but the registrant will file such required
               financial statements, if required pursuant to this item and Rule
               3-05(b) of Regulation S-X, by amendment to this report as soon as
               practicable, but not later than sixty days after this report was
               required to be filed initially.
  
           (c) Exhibits.
  
      2.1  Agreement and Plan of Merger by and among CMGI, Inc., Fremont
           Corporation and Flycast Communications Corporation dated September
           29, 1999.
  
      2.2  Stock Option Agreement by and among CMGI, Inc. and Flycast
           Communications Corporation dated September 29, 1999.
  
                                       -2-
  <PAGE>
  
                                    SIGNATURE
  
       Pursuant to the requirements of the Securities Exchange Act of 1934, the
  registrant has duly caused this report to be signed on its behalf by the
  undersigned hereunto duly authorized.
  
                                      FLYCAST COMMUNICATIONS CORPORATION
  
  
                                      /s/ Thomas L. Marcus
                                      --------------------
                                      Thomas L. Marcus, Executive Vice President
                                      of Finance, Administration and Corporate
                                      Development
  
                                      Date:  October 12, 1999
  
                                       -3-
  <PAGE>
  
                                INDEX TO EXHIBITS
  
   Exhibit Number                        Description
   --------------    -----------------------------------------------------------
        2.1          Agreement and Plan of Merger by and among CMGI, Inc.,
                     Fremont Corporation and Flycast Communications Corporation
                     dated September 29, 1999.
  
        2.2          Stock Option Agreement by and among CMGI, Inc. and Flycast
                     Communications Corporation dated September 29, 1999.
  
                                       -4-
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metadata_filer: {"company-data": {"conformed-name": "FLYCAST COMMUNICATIONS CORP", "cik": "0001078292", "assigned-sic": "7311", "irs-number": "770431028", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "000-25467", "film-number": "99727169"}, "business-address": {"street1": "181 FREMONT STREET SUITE 120", "city": "SAN FRANCISCO", "state": "CA", "zip": "94105", "phone": "4159771000"}, "mail-address": {"street1": "181 FREMONT STREET SUITE 120", "city": "SAN FRANCISCO", "state": "CA", "zip": "94105"}}
text: SECURITIES AND EXCHANGE COMMISSION
  
                             WASHINGTON, D.C. 20549
  
                                    FORM 8-K
  
                                 CURRENT REPORT
  
     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
  
     Date of Report (Date of earliest event reported):  September 29, 1999.
  
                       FLYCAST COMMUNICATIONS CORPORATION
             (Exact name of registrant as specified in its charter)
  
            DELAWARE                   00025467                   77-0431028
        (State or other          (Commission File Number)       (IRS Employer
  jurisdiction of incorporation)                             Identification No.)
  
                               181 FREMONT STREET
                        SAN FRANCISCO, CALIFORNIA  94105
                     --------------------------------------
                     Address of principal executive offices
  
                                 (415) 977-1000
                     --------------------------------------
               Registrant's telephone number, including area code
  
  --------------------------------------------------------------------------------
  ITEM 2.  ACQUISITION OR DISPOSITION OF ASSETS
  
       On September 29, 1999, CMGI, Inc., a Delaware corporation ("CMGI"), agreed
  to acquire Flycast Communications Corporation, a Delaware corporation
  ("Flycast"), through a merger of Fremont Corporation, a Delaware corporation and
  a wholly owned subsidiary of CMGI (the "Transitory Subsidiary") with and into
  Flycast, as a result of which the stockholders of Flycast will become
  stockholders of CMGI.  Under the terms of the agreement, CMGI will issue .4738
  shares for every share of Flycast held on the closing date of the transaction.
  The close of the merger, expected in January 2000, is subject to customary
  conditions, including formal approval by Flycast stockholders.  A copy of the
  Agreement and Plan of Merger, by and among CMGI, Flycast and Transitory
  Subsidiary, dated September 29, 1999, is attached hereto as Exhibit 2.1.
  
       In connection with the merger, CMGI and Flycast also entered into a Stock
  Option Agreement, whereby Flycast granted CMGI an option to purchase up to
  3,036,750 shares of common stock at a cash purchase price equal to $47.53 per
  share; provided, however, that the number of shares issuable to CMGI shall not
  exceed 19.9% of the outstanding shares of Flycast common stock.  The option may
  be exercised by CMGI in the event that the merger is terminated under certain
  circumstances.  A copy of the Stock Option Agreement, by and among CMGI and
  Flycast, dated September 29, 1999, is attached hereto as Exhibit 2.2.
  
  ITEM 7.  FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS
  
           (a) It is impracticable for the registrant to provide the required
               financial statements for the business acquired at the time of
               filing this report, but the registrant will file such required
               financial statements, if required pursuant to this item and Rule
               3-05(b) of Regulation S-X, by amendment to this report as soon as
               practicable, but not later than sixty days after this report was
               required to be filed initially.
  
           (c) Exhibits.
  
      2.1  Agreement and Plan of Merger by and among CMGI, Inc., Fremont
           Corporation and Flycast Communications Corporation dated September
           29, 1999.
  
      2.2  Stock Option Agreement by and among CMGI, Inc. and Flycast
           Communications Corporation dated September 29, 1999.
  
                                       -2-
  SIGNATURE
  
       Pursuant to the requirements of the Securities Exchange Act of 1934, the
  registrant has duly caused this report to be signed on its behalf by the
  undersigned hereunto duly authorized.
  
                                      FLYCAST COMMUNICATIONS CORPORATION
  
                                      /s/ Thomas L. Marcus
                                      --------------------
                                      Thomas L. Marcus, Executive Vice President
                                      of Finance, Administration and Corporate
                                      Development
  
                                      Date:  October 12, 1999
  
                                       -3-
  INDEX TO EXHIBITS
  
   Exhibit Number                        Description
   --------------    -----------------------------------------------------------
        2.1          Agreement and Plan of Merger by and among CMGI, Inc.,
                     Fremont Corporation and Flycast Communications Corporation
                     dated September 29, 1999.
  
        2.2          Stock Option Agreement by and among CMGI, Inc. and Flycast
                     Communications Corporation dated September 29, 1999.
  
                                       -4-