Reducing unsolicited instant messages by tracking communication threads

Processes and techniques for reducing spam over instant messaging (SPIM) are described. In one implementation, the number of open instant messaging threads (''chat threads'') that a specific user canhave at a given time is limited to prevent a potential spimmer from flooding instant messaging users with SPIM. Another implementation combines the technique of limiting the number of open instant messaging threads with a user feedback technique that enables users to inform an instant messaging service or other entity about users that are sending SPIM or other undesirable content. Another implementation combines the technique of limiting the number of open instant messaging threads with a text analysis technique that enables an instant messaging service or other entity to analyze text generated by a user to determine if the user is sending SPIM or other undesirable content to other instant messaging users.