A system for conveniently removing recipients from a message being added to a message thread that enables a user to filter people from a recipient list of a message being added to a message thread. The system advantageously enables a user to filter out potential recipients based on a) their previous non-participation in the thread, b) their lack of registered interest in a topic of the thread, and/or c) their being listed only as recipients by way of their being contained in a group indicated in the recipient list.