A recent by Forrester Research has determined that participation in social networking sites has skyrocketed. In fact, nearly half of all adults (42%) in the United States are active on one or more social networking sites–with Facebook accounting for much of this growth. This has incredible effects on the world of international reputation management, because these sites have a range of effects on search results.
http://www.forrester.com/Research/Document/Excerpt/0,7211,55132,00.html