Clay Shirky gives a TED (www.ted.com) 16 minute presentation on how social media changes the dynamics of power and communications because it creates the possibility of masses communicating with masses. A compelling account of what communicators and politicians everywhere need to understand.
Clay wrote a book called ‘Here Comes Everybody: The Power of Organizing Without Organizations‘ which looks interesting. His site/blog also contains some more background on his thinking and approach. He is a consultant to international organisations like Nokia and the BBC and a professor at NYU.