http://comscore.com/Press_Events/Pre...core_Ad_Metrix
And its growing. Check out the list of top sites that have the juiciest social network traffic
?Over the past few years, social networking has become one of the most popular online activities, accounting for a significant portion of the time Internet users spend online and the pages they consume,? said Jeff Hackett, comScore senior vice president. ?Social networking sites now account for one out of every five ads people view online. Because the top social media sites can deliver high reach and frequency against target segments at a low cost, it appears that some advertisers are eager to use social networking sites as a new advertising delivery vehicle.?