The Social Media Classroom is a new project started by Howard Rheingold which offers an open-source Drupal-based web service to teachers and students for the purpose of introducing social media into the classroom. The service includes tools like forums, blogs, wikis, chat, social bookmarking, RSS, microblogging, widgets, video conferencing, and more.
Disruptive technologies, pedagogical innovation: What's new: Findings from an in-depth study of students use and perception of technology. Computers & Education 2008 50 (2): 511-524.