http://pewinternet.org/Reports/2011/Technology-and-social-networks.aspx

OVERVIEW
Questions have been raised about the social impact of widespread use of social networking sites like Facebook, LinkedIn, MySpace, and Twitter. Do these technologies isolate people and truncate their relationships? Or are there benefits associated with being connected to others in this way? The Pew Research Center’s Internet & American Life Project decided to examine social networking sites in a survey that explored people’s overall social networks and how use of these technologies is related to trust, tolerance, social support, and community and political engagement.

The findings presented here paint a rich and complex picture of the role that digital technology plays in people’s social worlds. Wherever possible, we seek to disentangle whether people’s varying social behaviors and attitudes are related to the different ways they use social networking sites, or to other relevant demographic characteristics, such as age, gender and social class.

ABOUT THE SURVEY
The results in this report are based on data from telephone interviews conducted by Princeton Survey Research Associates International from October 20 to November 28, 2010, among a sample of 2,255 adults, age 18 and older. Interviews were conducted in English, via landline and cell phone. For results based on the total sample, one can say with 95% confidence that the error attributable to sampling is plus or minus 2.5 percentage points. For results based on internet users (n=1,787), the margin of sampling error is plus or minus 2.8 percentage points.