Hmmm, thanks Harold, for that thoughtful post, which I found very useful. I feel there is a powerful overlap between collaboration, development and these emerging social networking platforms. So much so that I have built a collaborative leadership development platform www.TheLeadershipHub.com . My guess is that if the 'triviality' of a lot of the interaction on Facebook et all is replaced with informal collaborative learning - as with Sermo for physicians, where a physician with a puzzling case can call on the brains and experience of 25,000 other members and ask their advice - then that's the way that these Web 2.0 sites will reach into the business and professional community. It will be as collaboration rather than just networking platforms that most value is added. There's a lot of disillusionment with MBAs, leadership training and courses, yet tremendous demand for improved leadership. 70% of our learning in life is informal. Hence the power of collaborative communities.