20% of Americans play games on social networks

"According to Social Network Gaming, the most recent report from leading market research company, The NPD Group, 20 percent of the U.S. population ages 6 and older reports having played a game on a social network in the past three months.  This equates to 56.8 million U.S. consumers, which is a significant number for a relatively new gaming activity.
According to the report, 35 percent of social network gamers are new to gaming, never having  participated in any other type of gaming before they started playing games on social networks. Females and older age groups are more likely to be new gamers than other groups measured in the study.
Interestingly, despite the perception that social network gamers are primarily females, the study finds that social network gamers are fairly evenly divided between genders, at 47 percent male, and 53 percent female."
Source:  Press release from NPD, 23rd August 2010