Businessweek Charts Social Media Participation by Age Group

Not surprisingly, youth is controlling the content flow in social media according to a Businessweek graph depicting various age groups' participation in social media. The groups are then split into 6 groups: Creators, Critics, Collectors, Joiners, Spectators and Inactives.

The chart doesn't measure influence, which is really what matters in social media. It remains to be seen who will emerge as most influential in social media networks, but my bet is on the over 30 demographic that dominates blog influence.

via PSFK

Forrester, source of this data, calls this "social technographics." You're right, there's not more data on influence, which is difficult to capture in consumer-reported data - but I'm sure a brand monitoring company could take this as a start and expand on it. More on social technographics here: http://blogs.forrester.com/charleneli/2007/04/forresters_new_.html