Thread Arcs is a novel interactive visualization technique designed to help people use threads found in email. Thread Arcs combine the chronology of messages with the branching tree structure of a conversational thread in a mixed-model visualization that is stable and compact. By quickly scanning and interacting with Thread Arcs, people can see various attributes of conversations and find relevant messages in them easily.
Thread Arcs, which resulted in a published paper, is a truly interesting visual approach to e-mail threads and even to small sized graphs. This concept is part of a major project developed by the Collaborative User Experience team at IBM Research entitled ReMail. It's being developed for almost a decade and it aims at better understanding how people use e-mail and make the experience more functional and straightforward. Some of its features are very encouraging.