• by Gavin O'Malley  @mp_gavin, November 28, 2011

No wonder Hulu’s owners decided not to sell their stakes in the video venture. Ad-supported streaming media is on fire.

In October alone, Americans viewed 7.5 billion video ads, with Hulu generating the highest number of video ad impressions at more than 1.3 billion, according to comScore Video Metrix.  

With the average viewer now consuming a record 21.1 hours of video a month, a total of 184 million U.S. Web users -- or 86.2% of the country’s online population -- watched more than 42 billion videos in October, comScore found.

Also worth noting, video ads accounted for 14.9% of all videos viewed -- and 1.4% of all minutes spent viewing video online -- in October.

Led by YouTube, Google sites still ranked as the top online video content property in October, with 161 million unique viewers and a record 20.9 billion videos viewed.

Still small by comparison, Facebook.com ranked second with 59.8 million viewers; followed by Vevo with 57 million; Microsoft sites with 49.1 million; and Viacom Digital with 48.2 million.

In the ad-serving category, Tremor Video ranked second overall -- and highest among video ad exchanges/networks -- crossing the 1 billion mark for the first time.

BrightRoll Video Network ranked third with 756 million, followed by Specific Media with 512 million; and CBS Interactive with 415 million.

Time spent watching video ads totaled more than 3.2 billion minutes during the month, with Tremor Video delivering the highest duration of video ads at 614 million minutes.

Across the board, video ads reached 53% of the total U.S. population an average of 47 times during the month, while Hulu delivered the highest frequency of video ads to its viewers with an average of 46.5.

Among YouTube partners, video music channels Vevo and Warner Music maintained the top two positions in October, with 54.2 million viewers and 30.4 million viewers, respectively.

Gaming channel Machinima ranked third with 17.7 million viewers; followed by Schmooru with 9.9 million; Maker Studios with 9.4 million; and Demand Media with 7.4 million.

Within the top 10 partners, Machinima demonstrated the highest engagement with 65.1 minutes per viewer on average, and it accounted for the second-highest number of videos viewed -- 277 million -- after Vevo.