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                                                                   EXHIBIT 10.15

                                JOINDER AGREEMENT

     THIS JOINDER AGREEMENT (this "Agreement") is made as of the 6th day of
March, 2000 by and among eBay, Inc., a Delaware corporation ("eBay"), Manheim
ATC, Inc., a Delaware corporation ("Manheim"), and AutoTrader.com, LLC, a
Delaware limited liability company (the "Company").

                                    RECITALS:

     A. The Company, Manheim, ADP, Inc., a Delaware corporation ("ADP"), LTM
Company L.P., a Virginia limited partnership ("Landmark"), ATC Holdings, Inc., a
Nevada corporation ("ATCHI"), and KPCB Holdings, Inc, as nominee ("KPCB"), are
parties to that certain Amended and Restated Registration Rights Agreement,
dated as of August 20, 2000 (the "Registration Rights Agreement"), pursuant to
which the Company has granted Manheim, ADP, Landmark, ATCHI and KPCB certain
registration rights with respect to the Company's Class A Units.

     B. eBay and the Company are parties to that certain Unit Purchase
Agreement, dated as of March 6, 2000 (the "Unit Purchase Agreement"), pursuant
to which the Company has agreed to issue and sell to eBay three percent (3%) of
the Company's limited liability company membership Units, determined on a fully
diluted basis (the "Purchase Units").

     C. The Company wishes to grant registration rights to eBay under the
Registration Rights Agreement and to add eBay as a Holder under the terms of the
Registration Rights Agreement.

     In consideration of the mutual covenants contained herein, the receipt and
sufficiency of which are hereby acknowledged, the parties hereby agree as
follows:

     1. Joinder. In accordance with Section 11.4 of the Registration Rights
Agreement, by the execution of this Agreement, eBay hereby agrees to become, and
to be deemed for all purposes to be, a signatory to the Registration Rights
Agreement and an additional Holder thereunder, and eBay shall be entitled to all
of the rights and benefits of an additional Holder in accordance with the terms
of the Registration Rights Agreement. eBay agrees to be bound by all of the
terms and conditions applicable to it as an additional Holder under the
Registration Rights Agreement with respect to the Purchase Units. In accordance
with Section 11.4 of the Registration Rights Agreement, each of the Company and
Manheim, as the holder of a majority of the outstanding Registrable Securities,
hereby consents and approves the addition of eBay as an additional Holder under
the Registration Rights Agreement.

     2. Governing Law. This Agreement shall be governed by and construed in
accordance with the substantive laws of the State of Delaware without regard to
its conflict of laws provisions.


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     3. Further Assurances. The parties hereto each agree to perform any further
acts and execute and deliver any additional documents that may be reasonably
necessary to carry out the provisions of this Agreement or the Registration
Rights Agreement.

     4. Binding Effect. This Agreement and the Registration Rights Agreement
shall be binding upon, and shall inure to the benefit of, each of the parties
hereto and their respective successors and assigns.

     5. Capitalized Terms. All capitalized terms used but not otherwise defined
in this Agreement shall have the same meaning as set forth in the Registration
Rights Agreement.

     6. Amendments. This Agreement and any of the provisions hereof may not be
amended, altered or added to in any manner except by a document in writing
signed by each party.

     7. Counterparts. This Agreement may be executed in two or more
counterparts, each of which shall be deemed and original, but all of which
together shall constitute one and the same instrument.

                      [SIGNATURES APPEAR ON FOLLOWING PAGE]


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     IN WITNESS WHEREOF, this Agreement has been executed by the parties hereto
as of the date first above written.

                                    COMPANY:

                                    AUTOTRADER.COM, LLC


                                    By: /s/ Andrew A. Merdek
                                       -----------------------------
                                    Name: Andrew A. Merdek
                                         ---------------------------
                                    Title: Secretary
                                          --------------------------


                                    EBAY:

                                    eBay, Inc.


                                    By: /s/ Brian Swette
                                       -----------------------------
                                    Name: Brian Swette
                                         ---------------------------
                                    Title: Chief Operating Officer
                                          --------------------------


                                    MANHEIM:

                                    MANHEIM ATC, INC.


                                    By: /s/ Andrew A. Merdek
                                       -----------------------------
                                    Name: Andrew A. Merdek
                                         ---------------------------
                                    Title: Secretary
                                          --------------------------