For those of you interested in social networking/Web 2.0 technologies, check out this link on Brian Solis PR 2.0 blog, which contains some in depth data on the user profiles for the 20 most widely used social networking sites (including Facebook, Twitter and LinkedIn) for the 12 months to May 2009. The link to the full report is here…
http://www.briansolis.com/2009/10/revealing-the-people-defining-social-networks/
however here's a graphic that summarizes the figures…