A site where you can have a secure, optionally private, ad-free wiki of your very own for a few dollars a month, or an insecure, ad-infested, public wiki for free. Neat-O.
K. Lochbaum, B. Grosz, and C. Sidner. Proceedings of the Eighth National Conference on Artificial Intelligence, page 485-490. Menlo Park, California, AAAI Press, (1990)
T. Gross, S. Braun, and S. Krause. Proceedings of the Fourteenth Euromicro Conference on Parallel, Distributed, and Network-Based Processing - PDP 2006, page 308-315. Los Alamitos, CA, USA, IEEE Computer Society Press, (15-17 February 2006)
S. Fussell, R. Kraut, and J. Siegel. CSCW '00: Proceedings of the 2000 ACM conference on Computer supported cooperative work, page 21-30. New York, NY, USA, ACM Press, (2000)