As Filed with the Securities and Exchange Commission on October 31, 2005

                                                     Registration No. 333-124303



                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                 POST-EFFECTIVE
                                 AMENDMENT NO. 3
                                       TO
                                    FORM S-4
             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
                               IAC/INTERACTIVECORP
             (Exact Name of Registrant as Specified in its Charter)

   Delaware                           4833                       59-2712887
(State or Other           (Primary Standard Industrial        (I.R.S. Employer
Jurisdiction of           Classification Code Number)         Identification
Incorporation or                                                  Number)
 Organization)

                              152 WEST 57TH STREET
                            NEW YORK, NEW YORK 10019
                                 (212) 314-7300
          (Address, including Zip Code, and Telephone Number, including
             Area Code, of Registrant's Principal Executive Offices)

                             GREGORY R. BLATT, ESQ.
             EXECUTIVE VICE PRESIDENT, GENERAL COUNSEL AND SECRETARY
                               IAC/INTERACTIVECORP
                              152 WEST 57TH STREET
                            NEW YORK, NEW YORK 10019
                                 (212) 314-7300
            (Name, Address, including Zip Code, and Telephone Number,
                   including Area Code, of Agent For Service)

                                    COPY TO:
                             PAMELA S. SEYMON, ESQ.
                         WACHTELL, LIPTON, ROSEN & Katz
                               51 West 52nd Street
                            New York, New York 10019
                                 (212) 403-1000

        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon
as practicable after this Registration Statement becomes effective and upon
completion of the transactions described in the enclosed proxy
statement/prospectus.


        If the securities registered on this form are being offered in
connection with the formation of a holding company and there is compliance with
General Instruction G, check the following box. [ ]

        If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the
"Securities Act"), check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [ ]

        If this form is a post-effective amendment filed pursuant to Rule 462(d)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [ ]

        THIS POST-EFFECTIVE AMENDMENT NO. 3 TO REGISTRATION STATEMENT ON FORM
S-4 (REG. NO. 333-124303) SHALL HEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 8(C) OF THE SECURITIES ACT OF 1933.

                                EXPLANATORY NOTE

        This Post-Effective Amendment No. 3 to Form S-4 Registration Statement
No. 333-124303 is filed solely to file Exhibit 8.1a as an additional exhibit to
the Registration Statement. In accordance with Section 462(d) of the Securities
Act of 1933, as amended, this Post-Effective Amendment shall become effective
immediately upon filing with the Securities and Exchange Commission.



                 PART II--INFORMATION NOT REQUIRED IN PROSPECTUS

Item 21.    Exhibits and Financial Statement Schedules.

                                  EXHIBIT INDEX



Exhibit No.     Document

    8.1a        Opinion of Wachtell, Lipton, Rosen & Katz, as to certain
                material U.S. federal tax matters








                                   SIGNATURES

        Pursuant to the requirements of the Securities Act, the co-Registrant
has duly caused this Post-Effective Amendment to be signed on its behalf by the
undersigned, thereunto duly authorized in the City of New York, State of New
York, on October 31, 2005.


                                         IAC/INTERACTIVECORP


                                         By: /s/  GREGORY R. BLATT
                                         -------------------------------------
                                         Name:    Gregory R. Blatt
                                         Title:   Executive Vice President,
                                                  General Counsel and Secretary

         IN WITNESS WHEREOF and pursuant to the requirements of the Securities
Act, this Post-Effective Amendment has been signed by the following persons in
the capacities indicated as of October 31, 2005.


             Signature                                     Title



                *

- ------------------------------------     Chairman of the Board, Chief Executive
            Barry Diller                         Officer and Director


                *
- ------------------------------------
         Victor A. Kaufman                   Vice Chairman and Director



                *
- ------------------------------------
        Thomas J. McInerney                  Executive Vice President and
                                                Chief Financial Officer



                *
- -----------------------------------
        Michael H. Schwerdtman                Vice President and Controller
                                                (Chief Accounting Officer)




                *
- ------------------------------------
         Edgar Bronfman, Jr.                           Director



                *
- ------------------------------------
         Donald R. Keough                              Director






                *
- ------------------------------------
         Marie-Josee Kravis                            Director



                *
- ------------------------------------
            Bryan Lourd                                Director


                *
- ------------------------------------
         Arthur C. Martinez                            Director



                *
- ------------------------------------
          Steven Rattner                               Director



                *
- ------------------------------------
      H. Norman Schwarzkopf                            Director



                *
- ------------------------------------
         Alan G. Spoon                                 Director



                *
- ------------------------------------
     Diane Von Furstenberg                             Director



*By:
       /s/  GREGORY R. BLATT
       -------------------------
            Gregory R. Blatt








                                                                    EXHIBIT 8.1A

                                 August 9, 2005




Board of Directors
IAC/InterActiveCorp
152 West 57th Street
New York, New York  10019

Ladies and Gentlemen:

         We have acted as special counsel to IAC/InterActiveCorp, a Delaware
corporation ("IAC"), in connection with the transactions, including the
Separation and the Reclassification (the Separation and the Reclassification,
taken together, the "Distribution") contemplated by the Separation Agreement,
dated as of August 9, 2005, by and between IAC and Expedia, Inc., a Delaware
corporation and a direct wholly-owned subsidiary of IAC ("Expedia"). At your
request, we are rendering our opinion as to certain United States federal income
tax consequences of the Distribution. Except as otherwise provided, all
capitalized terms used but not defined herein shall have the meanings ascribed
to them in the Separation Agreement.

         In that connection, we have reviewed (i) the Separation Agreement and
the Ancillary Agreements, (ii) the registration statement on Form S-4 relating
to the Distribution (the "Registration Statement"), (iii) IAC's annual reports
on Form 10-K for its fiscal years ended December 31, 2003 and 2004, and IAC's
proxy or information statements relating to meetings of, or actions taken
without a meeting by, IAC's shareholders held since December 31, 2003 (the items
described in clauses (ii) and (iii), collectively, the "SEC Filings"), (iv) a
letter, dated August 9, 2005, from one of IAC's financial advisers addressed to
IAC's Board of Directors and to us, substantiating the corporate business
purpose for the Distribution (the "Banker Letter"), (v)(A) a representation
letter addressed to IAC, dated August 9, 2005, from certain entities affiliated
with Liberty Media Corporation, and (B) a representation letter addressed to
IAC, dated August 9, 2005, from BDTV Inc., BDTV II, Inc., BDTV III, Inc., and
BDTV IV, Inc. (the representation letters in clauses (A) and (B), the
"Shareholder Letters"), and (vi) such other documents as we have deemed
necessary or appropriate in order to give the opinion set forth herein.

          For purposes of the opinion set forth below, we have relied, with the
consent of IAC, upon the accuracy and completeness of the statements and
representations (which statements and representations we have neither
investigated nor verified) contained in the representation letter of IAC and
Expedia dated the date hereof (including all of the information and
representations set forth in the documents attached thereto as Appendix A), and
have assumed that such statements and representations will be accurate and
complete as of the time of the Distribution and that all such statements and
representations made to the knowledge of any person or entity or with similar
qualification are and will be true and correct as if made without such
qualification. We have also relied upon the accuracy of the SEC Filings, the
Banker Letter and the Shareholder Letters.

          We have assumed that the Distribution and related transactions (i)
will be consummated as described in the Registration Statement and in accordance
with the Separation Agreement (and that none of the covenants or conditions set
forth in the Separation Agreement will be waived or modified), and (ii) will be
reported by IAC on its federal income tax return in a manner consistent with the
opinions set forth below.

          Based upon and subject to the foregoing, it is our opinion, under
currently applicable United States federal income tax law, that:

         (1) the transfer by IAC of certain assets in constructive exchange for
Expedia common stock and the assumption by Expedia of certain related
liabilities, if any, followed by the Distribution, will qualify as a
reorganization under Sections 355 and 368(a)(1)(D) of the Internal Revenue Code
of 1986, as amended (the "Code");

         (2) no gain or loss will be recognized by, and no amount will be
includible in the income of, IAC on the Distribution, other than with respect to
any distribution received by IAC, or any "excess loss account" or "intercompany
transaction" required to be taken into account under Treasury Regulations
relating to consolidated returns;

         (3) no gain or loss will be recognized by, and no amount will be
includible in the income of, a holder of IAC common stock solely as a result of
the receipt of IAC common stock in exchange therefor in the Reclassification;
and

         (4) no gain or loss will be recognized by, and no amount will be
includible in the income of, a holder of IAC common stock solely as a result of
the receipt of Expedia common stock in the Distribution.

          Our opinions apply only to holders of IAC common stock that are "U.S.
persons" for federal income tax purposes and that hold their IAC common stock as
a capital asset within the meaning of Section 1221 of the Code, and do not apply
to holders who acquired their IAC common stock through the exercise of options,
or otherwise as compensation, or who are otherwise subject to special treatment
under the U.S. federal income tax laws (including insurance companies, dealers
in securities or foreign currency, and financial institutions). This opinion
relates solely to the material United States federal income tax consequences of
the Distribution and certain related matters, and no opinion is expressed as to
the tax consequences under any foreign, state or local tax law or under any
federal tax laws other than those pertaining to the income tax.

          Our opinion is based on current provisions of the Code, Treasury
Regulations promulgated thereunder, published pronouncements of the Internal
Revenue Service and case law, any of which may be changed at any time with
retroactive effect. Any change in applicable laws or the facts and circumstances
surrounding the Distribution, or any inaccuracy in the statements, facts,
assumptions or representations upon which we have relied, may affect the
continuing validity of our opinions as set forth herein. We assume no
responsibility to inform IAC of any such change or inaccuracy that may occur or
come to our attention.

          We are furnishing this opinion solely to you in connection with the
transactions contemplated by the Separation Agreement and this opinion is not to
be relied upon for any other purpose or by any other person without our prior
written consent. We hereby consent to the filing of this opinion with the
Securities and Exchange Commission as an exhibit to Post-Effective Amendment No.
3 to the Registration Statement, and to the references therein to us. In giving
such consent, we do not thereby admit that we are in the category of persons
whose consent is required under Section 7 of the Securities Act of 1933, as
amended.



                                              Very truly yours,

                                              /s/ WACHTELL, LIPTON, ROSEN & KATZ