


<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549


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                                  SCHEDULE 13G
                                 (Rule 13d-102)

             INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
           TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED
                            PURSUANT TO RULE 13d-2(b)
                               (Amendment No. 2 )(1)


                                 About.Com, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    003736105
--------------------------------------------------------------------------------
                                 (CUSIP Number)

                                   03/31/2001
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

         |X|      Rule 13d-1(b)

         |_|      Rule 13d-1(c)

         |_|      Rule 13d-1(d)

--------------------

(1)  The remainder of this cover page shall be filled out for a reporting
     person's initial filing on this form with respect to the subject class of
     securities, and for any subsequent amendment containing information which
     would alter the disclosures provided in a prior cover page.

     The information required in the remainder of this cover page shall not be
     deemed to be "filed" for the purpose of Section 18 of the Securities
     Exchange Act of 1934 or otherwise subject to the liabilities of that
     section of the Act but shall be subject to all other provisions of the Act
     (however, SEE the NOTES).



<PAGE>


--------------------                                           -----------------
CUSIP No. 003736105                 13G                        Page 2 of 8 Pages
--------------------                                           -----------------


--------------------------------------------------------------------------------
  1.    NAMES OF REPORTING PERSONS
        I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

                            The TCW Group, Inc.
--------------------------------------------------------------------------------
  2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                       (a)   |_|
                                                                       (b)   |X|
--------------------------------------------------------------------------------
  3.    SEC USE ONLY

--------------------------------------------------------------------------------
  4.    CITIZENSHIP OR PLACE OF ORGANIZATION

                            Nevada corporation
--------------------------------------------------------------------------------
  NUMBER OF       5.   SOLE VOTING POWER                                     -0-
   SHARES         --------------------------------------------------------------
 BENEFICIALLY     6.   SHARED VOTING POWER                                   -0-
   OWNED BY       --------------------------------------------------------------
    EACH          7.   SOLE DISPOSITIVE POWER                                -0-
  REPORTING       --------------------------------------------------------------
PERSON WITH       8.   SHARED DISPOSITIVE POWER                              -0-
--------------------------------------------------------------------------------
  9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                                                                             -0-
--------------------------------------------------------------------------------
 10.    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*
                                                                             |_|
--------------------------------------------------------------------------------
 11.    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
            0.0% (see response to Item 4)
--------------------------------------------------------------------------------
 12.    TYPE OF REPORTING PERSON*
        HC/CO
--------------------------------------------------------------------------------

                      *SEE INSTRUCTIONS BEFORE FILLING OUT

<PAGE>

--------------------                                           -----------------
CUSIP No. 003736105                 13G                        Page 3 of 8 Pages
--------------------                                           -----------------


--------------------------------------------------------------------------------
  1.    NAMES OF REPORTING PERSONS
        I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

                            Robert Day
--------------------------------------------------------------------------------
  2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                       (a)   |_|
                                                                       (b)   |X|
--------------------------------------------------------------------------------
  3.    SEC USE ONLY

--------------------------------------------------------------------------------
  4.    CITIZENSHIP OR PLACE OF ORGANIZATION

                            United States Citizen
--------------------------------------------------------------------------------
  NUMBER OF       5.   SOLE VOTING POWER                                     -0-
   SHARES         --------------------------------------------------------------
 BENEFICIALLY     6.   SHARED VOTING POWER                                   -0-
   OWNED BY       --------------------------------------------------------------
    EACH          7.   SOLE DISPOSITIVE POWER                                -0-
  REPORTING       --------------------------------------------------------------
PERSON WITH       8.   SHARED DISPOSITIVE POWER                              -0-
--------------------------------------------------------------------------------
  9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                                                                             -0-
--------------------------------------------------------------------------------
 10.    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*
                                                                             | |
--------------------------------------------------------------------------------
 11.    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
            0.0% (see response to Item 4)
--------------------------------------------------------------------------------
 12.    TYPE OF REPORTING PERSON*
        HC/IN
--------------------------------------------------------------------------------

                      *SEE INSTRUCTIONS BEFORE FILLING OUT


<PAGE>

                                                               Page 4 of 8 Pages


Item 1(a).   Name of Issuer:

             About.Com, Inc.

Item 1(b).   Address of Issuer's Principal Executive Offices:

             1440 Broadway, 19th Floor
             New York, NY 10018

Item 2(a).   Name of Persons Filing:
Item 2(b).   Address of Principal Business Office, or if None, Residence:
Item 2(c).   Citizenship:

             The TCW Group, Inc.
             865 South Figueroa Street
             Los Angeles, CA 90017
             (Nevada Corporation)

             Robert Day
             865 South Figueroa Street
             Los Angeles, CA 90017
             (United States Citizen)

Item 2(d).   Title of Class of Securities:

             Common Stock

Item 2(e).   CUSIP Number:

             003736105



<PAGE>

                                                               Page 5 of 8 Pages

Item 3. If This Statement Is Filed Pursuant toss.ss.240.13d-1(b), or
        240.13d-2(b) or (c), Check Whether the Person Filing is a:

        (a)  |_|  Broker or dealer registered under Section 15 of the Exchange
                  Act (15 U.S.C. 78o).
        (b)  |_|  Bank as defined in Section 3(a)(6) of the Act (15 U.S.C. 78c).
        (c)  |_|  Insurance company as defined in Section 3(a)(19) of the
                  Exchange Act (15 U.S.C.78c).
        (d)  |_|  Investment company registered under Section 8 of the
                  Investment Company Act of 1940 (15 U.S.C. 80a-8).
        (e)  |_|  An investment adviser in accordance with Section
                  240.13d-1(b)(1)(ii)(E).
        (f)  |_|  An employee benefit plan or endowment fund in accordance with
                  Section 240.13d-1(b)(1)(ii)(F).
        (g)  |X|  A parent holding company or control person in accordance with
                  Section 240.13d-1(b)(1)(ii)(G).

                         (SEE Item 7)
                         The TCW Group, Inc.
                         Robert Day (individual who may be deemed to control
                           The TCW Group, Inc. and other entities which hold the
                           Common Stock of the issuer)

        (h)  |_|  A savings association as defined in Section 3(b) of the
                  Federal Deposit Insurance Act (12 U.S.C. 1813);
        (i)  |_|  A church plan that is excluded from the definition of an
                  investment company under Section 3(c)(14) of the Investment
                  Company Act of 1940 (15 U.S.C. 80a-3);
        (j)  |_|  Group, in accordance with Section 240.13d-1(b)(1)(ii)(J).

       If this statement is filed pursuant to Rule 13d-1(c), check this box. |_|


<PAGE>

                                                               Page 6 of 8 Pages


Item 4.   Ownership **

          THE TCW GROUP, INC.
          (a)  Amount beneficially owned: none.
          (b)  Percent of class:  0.0%
          (c)  Number of shares as to which such person has:
               (i)   Sole power to vote or to direct the vote: none.
               (ii)  Shared power to vote or to direct the vote: none.
               (iii) Sole power to dispose or to direct the disposition of:
                     none.
               (iv)  Shared power to dispose or to direct the disposition of:
                     none.

          ROBERT DAY ***
          (a)  Amount beneficially owned: none.
          (b)  Percent of class:  0.0%
          (c)  Number of shares as to which such person has:
               (i)   Sole power to vote or to direct the vote: none.
               (ii)  Shared power to vote or to direct the vote: none.
               (iii) Sole power to dispose or direct the disposition of: none.
               (iv)  Shared power to dispose or to direct the disposition of:
                     none.


--------
**  The filing of this Schedule 13G shall not be construed as an admission
    that the reporting person or any of its affiliates is, for the purposes
    of Section 13(d) or 13(g) of the Securities Exchange Act of 1934, the
    beneficial owner of any securities covered by this Schedule 13G. In
    addition, the filing of this Schedule 13G shall not be construed as an
    admission that the reporting person or any of its affiliates is the
    beneficial owner of any securities covered by this Schedule 13G for any
    other purposes than Section 13(d) of the Securities Exchange Act of
    1934.

*** Shares reported for Robert Day include shares reported for The TCW Group,
    Inc.


<PAGE>

                                                               Page 7 of 8 Pages

Item 5.   Ownership of Five Percent or Less of a Class.

          If this statement is being filed to report the fact that as of the
          date hereof the reporting person has ceased to be the beneficial
          owner of more than five percent of the class of securities, check
          the following |X|.

Item 6.   Ownership of More than Five Percent on Behalf of Another Person.

          Not Applicable.

Item 7.   Identification  and  Classification of the Subsidiary Which Acquired
          the Security Being Reported on by the Parent Holding Company.

          SEE Exhibit A.

Item 8.   Identification and Classification of Members of the Group.

          Not applicable.  SEE Exhibits A and B.

Item 9.   Notice of Dissolution of Group.

          Not applicable.

Item 10.  Certification.

          Because this statement is filed pursuant to Rule 13d-1(b), the
          following certification is included:

          By signing below I certify that, to the best of my knowledge and
          belief, the securities referred to above were acquired in the
          ordinary course of business and were not acquired and are not held
          for the purpose of or with the effect of changing or influencing
          the control of the issuer of the securities and were not acquired
          and are not held in connection with or as a participant in any
          transaction having that purpose or effect.



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                                                               Page 8 of 8 Pages

                                    SIGNATURE


             After reasonable inquiry and to the best of my knowledge and
belief, I certify that the information set forth in this statement is true,
complete and correct.


Dated this 10th day of April, 2001.


                                             The TCW Group, Inc.

                                             By:  /s/ Linda D. Barker
                                                  ----------------------------
                                                  Linda D. Barker
                                                  Authorized Signatory







                                             Robert Day

                                             By:  /s/ Linda D. Barker
                                                  ----------------------------
                                                  Linda D. Barker

                                                  Under Power of Attorney dated
                                                  November 6, 2000, on file with
                                                  Schedule 13G for Retek, Inc.
                                                  dated November 8, 2000.


