(Source: PRNewswire-FirstCall)RESTON, Va., Sept. 1 /PRNewswire-FirstCall/ -- comScore, Inc. , a leader in measuring the digital world today released a study of U.S. online display advertising on social networking sites in July 2009, based on data from the comScore Ad Metrix service. The study showed that social networking sites accounted for more than 20 percent of all display ads viewed online, with MySpace and Facebook combining to deliver more than 80 percent of ads among sites in the social networking category.

   (Logo:  http://www.newscom.com/cgi-bin/prnh/20080115/COMSCORELOGO)     Top Online Display Ad Publishers in Social Networking Category   July 2009   Total U.S.