comScore's July 2011 data release for YouTube Partner Reporting reporting -- YouTube continued its dominance of the U.S. online video-viewing market in July, making owner Google the No. 1 online video content property in July, according to the latest comScore report.
YouTube accounted 158.1 million unique viewers, while VEVO ranked second with 62.1 million. Meanwhile, Facebook made a jump to #3 position, going from 47.7 million unique video viewers in June to 51.4 million in July, according to comScore.
Microsoft -- driving by Bing Video -- had 49.5 million unique viewers in July, down from 50.7 million unique viewers in June.
While YouTube has continued to maintain its lead in online video viewing, Microsoft and others such as Yahoo have lost ground to Facebook and VEVO.
The average viewer watched 18.5 hours of online video content in July, with YouTube (5.9 hours) and Hulu (3.4 hours) clocking in the highest engagement among viewers, according to comScore.
Americans viewed more than 5.3 billion video ads in July, with Hulu generating the highest number of video ad impressions at 963 million. Adap.tv ranked second overall (and highest among video ad exchanges/networks) with 674 million ad views.
"Video ads reached 49% of the total U.S. population an average of 35.9 times during the month. Hulu delivered the highest frequency of video ads to its viewers with an average of 40.4 over the course of the month," comScore reports.