FILING AGREEMENT BETWEEN THK PRIVATE EQUITIES AND THEODORE H. KRUTTSCHNITT III The undersigned hereby agree that the Schedule 13D with respect to the Common Stock, $.001 par value, of Exchange Applications, Inc. dated of even date herewith is and...

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                                                                       EXHIBIT 7


                                FILING AGREEMENT
                                     BETWEEN
                              THK PRIVATE EQUITIES
                                       AND
                          XXXXXXXX X. XXXXXXXXXXXX III


        The undersigned hereby agree that the Schedule 13D with respect to the
Common Stock, $.001 par value, of Exchange Applications, Inc. dated of even date
herewith is and shall be filed on behalf of both of us pursuant to and in
accordance with the provisions of Rule 13d-1(k)(1) under the Securities Exchange
Act of 1934, as amended.

Dated:  September 18, 2001

                                     THK PRIVATE EQUITIES



                                     By: /s/ Xxxxxxxx X. Xxxxxxxxxxxx III
                                         --------------------------------
                                         Xxxxxxxx X. Xxxxxxxxxxxx III
                                         Sole Proprietor








                                         /s/ Xxxxxxxx X. Xxxxxxxxxxxx III
                                         --------------------------------
                                         Xxxxxxxx X. Xxxxxxxxxxxx III