Leading the increase in social networking usage were those over the age of 35, which grew nearly twice as fast as those 18-35 in the same time period.  Only 18% of Internet users over the age of 35 used a social networking service in 2008 and by 2010 that number was up to 48%. The average age of an adult SNS user jumped from 33 years old in 2008 to 38 years old in 2010. This entire Pew Research Center Report is fascinating.