• by Mark Walsh  @markfwal, March 4, 2008

Adding a new category to its index of Internet activity, the Online Publishers Association found that community sites--including social networks such as Facebook and MySpace--account for only 7.5% of time spent online.

That puts community sites ahead of search (5%), but well below content (42.7%), communications (28.7%), and commerce sites (16.1%) in time spent. The OPA defines the community category as Web sites and applications that combine user-generated content with communications to foster relationships among their members.

"The addition of Community reflects the increasing popularity of sites such as MySpace and Facebook that don't clearly fit into a single existing (Internet Activity Index) category, said OPA President Pam Horan. Even so, adding social networking sites to the mix hardly displaced content as king when it comes to monopolizing users' time online.

Separately, Web measurement firm HitWise estimates that social networking sites and other online forums, such as Craigslist, accounted for 9.3% of U.S. Internet traffic in February. Social networks alone made up almost 6% of traffic.

While still small, advertising on social sites is growing rapidly. In its recently released 2008 Digital Outlook Report, Avenue A|Razorfish identified entertainment and community sites as the two fastest-growing ad categories last year, with the latter growing more than 50% to $55 million.