Who and how many people use social networks?
The answer was answered by the Pew Internet Project in their recent report released yesterday.
Overall, among adult Internet users 1 of 3 has at least one profile. This is up from 1 in 12 just three short years ago. And yes, it skews young - ranging from 75% among the 18-24 segment to 7% of the 65+ audience.
They use it to connect with friends and family. It seems to be replacing the more synchronous and media restrictive platforms of bygone eras - like email and phones. The singular advantage of social networks as a communication platform is that they facilitate multiple connections over time, distance, and interests.