Outstanding lecture by Howard Rheingold regarding virtual communities and social media, participative, and digital literacies. Howard is one of the world's foremost authorities on the social implications of technology and is also the former University of California, Berkeley professor of both Berkeley Home School Prep Academy founders Christopher and Tracie Neal. 
Watch video at link below: 
http://www.youtube.com/watch?v=vRG_Xy6y5G0