

                                    EXHIBIT 5
             OPINION AND CONSENT OF BROBECK, PHLEGER & HARRISON LLP


                                February 16, 2000


About.com, Inc.
220 E. 42nd Street, 24th Floor
New York, New York 10017

            Re:   About.com, Inc.- Registration Statement for Offering of an
                  Aggregate of 498,937 Shares of Common Stock

Dear Ladies and Gentlemen:

            We have acted as counsel to About.com, Inc., a Delaware corporation
(the "Company"), in connection with the registration on Form S-8 (the
"Registration Statement") under the Securities Act of 1933, as amended, of an
aggregate of 498,937 shares of common stock (the "Shares") and related stock
options authorized for issuance under the ExpertCentral.com, Inc. 1999 Stock
Incentive Plan and the Amended and Restated 1999 Non-Officer Stock Option/Stock
Issuance Plan (the "Plans").

            This opinion is being furnished in accordance with the requirements
of Item 8 of Form S-8 and Item 601(b)(5)(i) of Regulation S-K.

            We have reviewed the Company's charter documents and the corporate
proceedings taken by the Company in connection with the establishment of the
Plans. Based on such review, we are of the opinion that, if, as and when the
Shares have been issued and sold (and the consideration therefor received)
pursuant to (a) the provisions of option agreements duly authorized under the
Plans and in accordance with the Registration Statement, or (b) duly authorized
direct stock issuances in accordance with the Plans and in accordance with the
Registration Statement, such Shares will be duly authorized, legally issued,
fully paid and nonassessable.

            We consent to the filing of this opinion letter as Exhibit 5 to the
Registration Statement.

            This opinion letter is rendered as of the date first written above
and we disclaim any obligation to advise you of facts, circumstances, events or
developments which hereafter may be brought to our attention and which may
alter, affect or modify the opinion expressed herein. Our opinion is expressly
limited to the matters set forth above and we render no opinion, whether by
implication or otherwise, as to any other matters relating to the Company, the
Plans or the Shares.

                                       Very truly yours,

                                       /s/ Brobeck, Phleger & Harrison LLP


                                       BROBECK, PHLEGER & HARRISON LLP

