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                                                                    Exhibit 99.4

                               PENTON MEDIA, INC.

                                   LETTER TO
                     DEPOSITORY TRUST COMPANY PARTICIPANTS

                          EXCHANGE OF ALL OUTSTANDING
                   10 3/8% SENIOR SUBORDINATED NOTES DUE 2011
                                      FOR
                   10 3/8% SENIOR SUBORDINATED NOTES DUE 2011

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        THE EXCHANGE OFFER WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME,

         ON NOVEMBER 15, 2001, UNLESS EXTENDED (THE "EXPIRATION DATE").

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OUTSTANDING NOTES TENDERED IN THE EXCHANGE OFFER MAY BE WITHDRAWN AT ANY TIME
PRIOR TO 5:00 P.M., NEW YORK CITY TIME, ON THE EXPIRATION DATE.

To Depository Trust Company Participants:


     We are enclosing herewith the material listed below relating to the offer
by Penton Media, Inc., to exchange its 10 3/8% Senior Subordinated Notes due
2011 (the "Exchange Notes"), which have been registered under the Securities Act
of 1933, as amended (the "Securities Act"), for a like principal amount of its
issued and outstanding 10 3/8% Senior Subordinated Notes due 2011 (the
"Outstanding Notes"), upon the terms and subject to the conditions set forth in
Penton's Prospectus, dated October 12, 2001, and the related letter of
transmittal (which together constitute the "Exchange Offer").


     Enclosed are copies of the following documents:


     1. Prospectus, dated October 12, 2001;


     2. Letter of Transmittal (together with accompanying Substitute Form W-9
        Guidelines);

     3. Notice of Guaranteed Delivery; and

     4. Letter that may be sent to your clients for whose account you hold
        Outstanding Notes in your name or in the name of your nominee, with
        space provided for obtaining such client's instruction with regard to
        the Exchange Offer.

     We urge you to contact your clients promptly. Please note that the Exchange
Offer will expire on the Expiration Date unless extended.

     The Exchange Offer is not conditioned upon any minimum number of
Outstanding Notes being tendered.

     Pursuant to the letter of transmittal, each holder of Outstanding Notes
will represent to Penton that:

      (i) any Exchange Notes that the holder will acquire in exchange for
          Outstanding Notes will be acquired in the ordinary course of business
          of the holder,

      (ii) the holder has not engaged in, does not intend to engage in, and has
           no arrangement with any person to engage in, a distribution of any
           Exchange Notes issued to the holder, and

     (iii) the holder is not an "affiliate" (as defined in Rule 405 under the
           Securities Act) of Penton.

     If the holder is a broker-dealer (whether or not it is also an "affiliate")
that will receive Exchange Notes for its own account in exchange for Outstanding
Notes, it will represent that the Outstanding Notes were acquired as a result of
market-making activities or other trading activities, and it will acknowledge
that it will deliver a prospectus meeting the requirements of the Securities Act
in connection with any resale of those Exchange Notes. By acknowledging that it
will deliver and by delivering a prospectus meeting the requirements of the
Securities Act in connection with any resale of those Exchange Notes, the
broker-dealer is not deemed to admit that it is an "underwriter" within the
meaning of the Securities Act.
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     The enclosed Letter to Clients contains an authorization by the beneficial
owners of the Outstanding Notes for you to make the foregoing representations.

     Penton will not pay any fee or commission to any broker or dealer to any
other persons (other than the Exchange Agent) in connection with the
solicitation of tenders of Outstanding Notes pursuant to the Exchange Offer.
Penton will pay or cause to be paid any transfer taxes payable on the transfer
of Outstanding Notes to it, except as otherwise provided in Instruction 6 of the
enclosed letter of transmittal.

     Additional copies of the enclosed material may be obtained from the
undersigned.

                                          Very truly yours,

                                          THE BANK OF NEW YORK