Laurence Brothers James D. Hollan Jakob Neilsen Scott Stornetta Steven P. Abney George W. Furnas Michael L. Littman Supporting Informal Communication via Ephemeral Interest Groups. 84-90 1992 CSCW http://doi.acm.org/10.1145/143457.143465 db/conf/cscw/cscw1992.html#BrothersHNSAFL92