I would like to add - Fraser, Matthew & Soumitra Dutta. Throwing Sheep in the Boardroom: How Online Social Networking Will Transform Your Life, Work and World. Wiley, 2009. In the July/Aug 2009 issue of Online (p.63) a review of this book states "If you have ever wondered how social networking developed and where it could lead us, this is the book to read. You will never look at Facebook, LinkedIn, or MySpace with same way again.” It not only sounds relevant and interesting, but the reviewer also calls it “a dense, thought-provoking book.”