SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                            SCHEDULE 14A INFORMATION

           Proxy Statement Pursuant to Section 14(a) of the Securities
                      Exchange Act of 1934 (Amendment No. )

Filed by the Registrant |X|
Filed by a Party other than the Registrant |_|

Check the appropriate box:

|_|   Preliminary Proxy Statement
|_|   Confidential, for Use of the Commission Only
      (as permitted by Rule 14a-6(e)(2)
|_|   Definitive Proxy Statement
|X|   Definitive Additional Materials
|_|   Soliciting Material Pursuant to ss.240.14a-11(c) or ss.240.14a-12

                               Vialog Corporation
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                (Name of Registrant as Specified In Its Charter)

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    (Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

|X|   No Fee Required

|_| Fee computed on table below per Exchange Act Rules 14a-6(i)(4) and 0-11.

      1.    Title of each class of securities to which transaction applies:

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      2.    Aggregate number of securities to which transaction applies:

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      3.    Per unit price or other underlying value of transaction computed
            pursuant to Exchange Act Rule 0-11 (set forth the amount on which
            the filing fee is calculated and state how it was determined):

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      4.    Proposed maximum aggregate value transaction:

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      5.    Total fee paid:

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|_| Fee paid previously with preliminary materials.

|_|   Check box if any part of the fee is offset as provided by Exchange Act
      Rule 0-11(a)(2) and identify the filing for which the offsetting fee was
      paid previously. Identify the previous filing by registration number, or
      the Form or Schedule and the date of its filing.

      1.    Amount previously paid:

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      2.    Form, Schedule or Registration Statement No.:

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      3.    Filing Party:

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      4.    Date Filed:

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                      [NOTICE TO REGISTERED SHAREHOLDERS]
[LOGO] Vialog
THE CONFERENCING COMPANY


32 Crosby Drive                                                   March 12, 2001
Bedford, MA 01730


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                 URGENT REMINDER - YOUR VOTE IS VERY IMPORTANT
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Dear Fellow Shareholder:

You have previously received proxy material in connection with the Special
Meeting of Shareholders of VIALOG CORPORATION. This meeting is to be held on
Friday March 23, 2001. According to our latest records, your PROXY VOTE for this
meeting HAS NOT BEEN RECEIVED.

Proposal One, to adopt the Agreement and Plan of Merger and Reorganization with
Genesys S.A., requires approval by an affirmative vote of 2/3rds of all shares
outstanding. If you do not vote your shares, you are essentially voting AGAINST
this proposal. Therefore, I would appreciate your immediate attention to the
enclosed proxy card.

Regardless of the number of shares you own, it is important that they be
represented at the meeting. Your vote matters to us and WE NEED YOUR SUPPORT.


    Since time remaining is short, we urge you to please vote using one of the
following methods:

o   Sign the proxy and fax it back to Corporate Investor Communications at
    201-804-8693, where CIC will expedite your vote and confirm that it is cast.

o   Sign the proxy and mail it back in the enclosed postage-paid envelope prior
    to the meeting date.


Thank you in advance for your support.


                                                Sincerely,


                                                Michael Savage
                                                Chief Financial Officer


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                          IF YOU HAVE RECENTLY VOTED,
              PLEASE ACCEPT OUR THANKS AND DISREGARD THIS REQUEST.
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