"The age of social media then is probably about a fusing of these two ways of thinking - the communicative and the publishing/creative parts of the internet - into something new and powerful. It's an environment in which every user is potentially a creator, a publisher and a collaborator with (and to) all of the other creative people on the internet.
(snip)
...It seems to me that the other main feature of social media is that they're looking at how each individual contribution can become part of something that's greater than the sum of its parts, and to feed that back to the individuals using the service so that - fundamentally - everyone gets back more than they're putting in. These new services are about creating frameworks and spaces, containers and supports that help users create and publish and use all kinds of data from the smallest comment to the best produced video clip which in aggregate create something of fascinating utility to all."

-- Tom Coates, "What do we do with social media?"