In case you haven't checked it out, the Interaction-Design.org Foundation is an outstanding project started by Mads Soegaard and Rikke Dam to create free and open educational materials for the HCI and IXD communities. The Encyclopedia of Human-Computer Interaction is the main project, where they've engaged professors and designers to contribute chapters that include HD video and commentary.
Mads and crew will soon release a chapter on Social Computing and its relation to social media, written by Tom Erickson, veteran researcher in social computing at IBM Watson Research Lab. The chapter includes multiple HD videos with interviews of Erickson.
These materials have apparently taken 10 months to produce and involved 3 editors, 2 peer-reviewers, and a camera crew of 4 people. There is also commentary by some renowned designers like Elizabeth Churchill from Yahoo Research and Andrea Forte from Drexel University.
The group have prepared a preview for Konigi readers. The text and HD videos are completely free and can be viewed here: http://interaction-design.org/encyclopedia/social_computing.html?p=0230.
This is an incredible new resource. Be sure to check it out.