Patent ID: 7058690

Claim:
A message exchange system in which at least a first client system used by a first user and a second client system used by a second user are connected to each other via at least one server system and a communication network and each client system exchanges a message via said server system, comprising: a storage device that stores a list for each user, registering information of one or more users to be subject to message exchange; said first client system comprising: a first deleting device that deletes registration information of said second user from a list of said first user based on an instruction from said first user; and a deletion requesting device that transmits a deletion request message, for deleting the registration information of said first user from a list of said second user, to said second client system via said server system when said first deleting device deletes the registration information of said second user from said list of said first user, and said second client system comprising: a second deleting device that deletes the registration information of said first user from said list of said second user when receiving said deletion request message from said server system.