Excellent piece pulling together theories, making them understandable and relating them to current practice and people. Possibly only missing Lave's concept of peripheral participation and community of practice. I have always assumed an affinity between the idea of a journey from periphery to centre of a community of practice and that journey across a ZPD
link to the post with discussion started by Robert Scoble arising from Google's real-name policy, which started a long conversation, pro and con, about the use of names on tinternet