The research demonstrates that MySpace has broad appeal across the ages and that 68% of its users are approaching their 30s.
The survey also revealed that 71% of visitors to Friendster.com are aged over 25. For brands wanting to tap into the minds of younger consumers, 20% of Xanga.com users are aged between 12 and 17, while 34% of Facebook.com's users are between 18 and 24 years old.
Jack Flanagan, comScore Media Metrix's executive vice-president, said: "While the top social networking sites are typically viewed as directly competing with one another, our analysis demonstrates that each site occupies a slightly different niche."