• by Wendy Davis  @wendyndavis, January 8, 2007

Several years ago, social networking sites were all but unknown to the general public, but today the majority of online U.S. teens have profiles on such sites.

The Pew Internet & American Life Project reported Sunday that 55% of all online American youngsters between the ages of 12 and 17 have created a profile on MySpace, Facebook, Xanga or another social networking site. That proportion is especially high for teen girls ages 15-17, with 70% of that group reporting that they have used online social networks, compared with 54% of boys between 15 and 17.

Why do teens turn to social networking sites? The vast majority--91%--say they do so to stay in contact with friends they also see frequently in the non-virtual world, while 82% say they use sites to stay in touch with people they don't see that often in person. Teens also go to the sites to make plans with friends (72%) and meet new friends (49%).

MySpace is far and away the leading social networking site with teens, with 85% of youngsters reporting that they have created profiles on the News Corp.-owned site. Seven percent used Facebook and 1% have done so Xanga, while less than 1% have created profiles on Yahoo, Piczo, Gaiaonline and Tagged.com, according to the report.