Here Comes Everybody : Clay Shirky
"Linux got to be world-changingly good not by promising to be great, or by bringing paid developers together under the direction of some master plan, but by getting incrementally better, through voluntary contributions, one version at a time." - Clay Shirky, Here Comes Everybody The social world does not run on averages. Shirky points out that there is no "average" social network. We have incredibly successful ones like facebook, and then lots of failed ones that we never even hear about.
This makes sense when you look at where the value lies in sociality. It isn't the people per se, but the connections between the people. New users strengthen social networks because a new user isn't just another person, it is another potential contact with every other person on the network.
Social media represents a new kind of Democracy--one in which we vote not by ballot, but by with our effort. With social media, we can pool our time, talents, and resources to effect changes that were impossible even 5 years ago.