I was unaware of the origin of the term "social networking". This support Dunbar's number suggested to be a theoretical cognitive limit to the number of people with whom one can maintain stable social relationships.
This Clay Shirky talk from Web 2.0 Expo NY ("It's Not Information Overload. It's Filter Failure") challenges the idea that we've got information overload problems (we've had more books than any human could read for hundreds of years), what we have is a series of filter failures, as our systems for managing information abundance are swamped by the growth of information. - boingboing