The share of adult internet users who have a profile on an online social network site has more than quadrupled in the past four years — from 8% in 2005 to 35% now, according to the Pew Internet & American Life Project’s December 2008 tracking survey.

Overall, personal use of social networks seems to be more prevalent than professional use of networks, both in the orientation of the networks that adults choose to use as well as the reasons they give for using the applications.