• by Jack Loechner , Staff Writer @mp_research, July 16, 2010

New data from comScore shows that 183 million U.S. Internet users watched online video during the month of May. YouTube.com achieved record levels of viewing activity with an all-time high of 14.6 billion videos viewed and surpassing the threshold of 100 videos per viewer for the first time.

U.S. Internet users watched nearly 34 billion videos in May, with Google Sites ranking as the top video property with 14.6 billion videos, representing 43.1% of all videos viewed online. YouTube accounted for the vast majority of videos viewed at the property. Hulu ranked second, Microsoft Sites ranked third followed by Vevo and Viacom Digital.

Google Sites attracted 144.6 million unique viewers during the month, followed by Yahoo! Sites and Vevo.

In May, Tremor Media ranked as the top video ad network with a potential reach of 56.2% of the total video viewing audience, while ScanScout Network ranked second with a potential reach of 54.3%.

Notable findings include:

• The top video ad networks in terms of their actual reach delivered were: Joost Video Network (by Adconion Media Group), BrightRoll Video Network, and Tremor Media Video Network
• 84.8% of the total U.S. Internet audience viewed online video
• 144.1 million viewers watched 14.6 billion videos on YouTube.com (101.2 videos per viewer).
• The average Hulu viewer watched 27.0 videos, totaling 2.7 hours of video per viewer.
• The duration of the average online video was 4.3 minutes.

For more information, please visit comScore here.