On January 14, 2009 Pew Internet & American Life Project released a new report on Adults and Social Network Websites. My younger daughter and I had been watch for a new report for the research statistics for her senior project at UT-Knoxville. It stated, "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..."
While media coverage and policy attention focus heavily on how children and young adults use social network sites, adults still make up the bulk of the users of these websites. Adults make up a larger portion of the US population than teens, which is why the 35% number represents a larger number of users than the 65% of online teens who also use online social networks.
Still, younger online adults are much more likely than their older counterparts to use social networks, with 75% of adults 18-24 using these networks, compared to just 7% of adults 65 and older. At its core, use of online social networks is still a phenomenon of the young.
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. Most adults, like teens, are using online social networks to connect with people they already know.
When users do use social networks for professional and personal reasons, they will often maintain multiple profiles, generally on different sites.
Most, but not all adult social network users are privacy conscious; 60% of adult social network users restrict access to their profiles so that only their friends can see it, and 58% of adult social network users restrict access to certain content within their profile. Source
A personal note: My daughters both have Facebook accounts. They told me that I am a "Cool" mom, but I CANNOT have a Facebook page. They think it is weird to be friends with other kids' moms. They said I don't need to know everything they do and read the "feed" of their friends. But they approved me Tweeting on Twitter! They said I "needed" that for my job! Love it! I am a "cool" mom! But sorry, you won't be seeing me on Facebook!