Social bookmarking site for academics

Inside HIgher Ed has an article about CiteULike, which is described as a nerdy version of Facebook or del.icio.us for academics. It's a social bookmarking tool that allows users to post, share and comment on each other’s links which, in this case, are citations to journal articles with titles like “Trend detection through temporal link analysis” and “The Social Psychology of Inter- and Intragroup Conflict in Governmental Politics.”