RESTON, VA: Monthly online video viewing sessions in the US reached an all-time high of 6.2 billion in June 2011, according to figures from comScore.
The research firm's Video Metrix service registered 178 million US internet users last month, with an average time per viewer of 16.8 hours. Online video was watched by 85.6% of the US internet audience.
Video ads represented 13.6% of all videos viewed, which equates to 1.3% of the total minutes.
Google Sites, which include YouTube, topped the comScore rankings with 149.3 million unique viewers.
The Google network also clocked the longest average viewership for the month at 324 minutes, and received the highest number of viewing sessions at 2.3 billion.
VEVO, which specialises in music videos, was ranked second in terms of reach with 63 million viewers.
This cohort averaged 112 minutes per viewer with just under 4 million viewing sessions.
They were followed in the rankings by Yahoo Sites, which attracted 52.7 million viewers in just under 2.5 million sessions. This equated to 34.8 minutes per viewer.
But Hulu, which specialises in rebroadcasting long-form TV shows from the major networks, led the way on the ad rankings, generating 1 billion video ad impressions. This equates to nearly 20% of the 5.3 billion total video ad viewings for June.
Hulu also delivered the highest frequency of video ads on the rankings, averaging 38.8 across the month.
Tremor Media Video Network, ranked second overall, with just over 750,000 impressions. Tremor also achieved the highest number of video ad minutes viewed at 429.
Overall, more than 2.2 billion minutes were spent watching videos during June 2011 in the US, with video ads reaching 49% of the population.
Each viewer watched an average of 35.6 video ads.
Data sourced from comScore; additional content by Warc staff