From Microsoft Research website...
SNARF, the Social Network and Relationship Finder, developed by Microsoft Research and available for download , is designed to help computer users cope with precisely such scenarios. SNARF, a complement to e-mail programs such as Outlook, filters and sorts e-mail based on the type of message and the user’s history with an e-mail correspondent. The result: a collection of alternative views of your e-mail that can help you make sense of the deluge
