Whetting the appetites of marketers, consumers are watching more online video advertising than ever. Breaking all previous records, Americans viewed more than 8.3 billion video ads in March, according to new data from comScore. Delivering another record month, Hulu recorded more than 1.7 billion video ad views in March, while Google Sites -- i.e., YouTube, ranked second with more than 1.2 billion video ads. The BrightRoll video network came in third with 953 million, followed by Adap.tv with 892 million, and Specific Media with more than 775 million. Time spent watching video ads totaled 3.5 billion minutes, with Hulu delivering the highest duration of video ads at 690 million minutes, according to comScore. Video ads reached 51% of the total U.S. population, an average of 53 times during the month, while Hulu delivered the highest frequency of video ads to its viewers with an average of 51, followed by ESPN, which delivered an average of 26 ads per viewer. Overall, 181 million U.S. Internet users watched nearly 37 billion online content videos in March, while video ads topped 8 billion for the first time on record. Google Sites, driven by YouTube.com, ranked as the top online video content property in March with 146.1 million unique viewers, followed by Yahoo Sites with 60.6 million; VEVO with 51.3 million; Facebook.com with 45.1 million; and Viacom Digital with 44.3 million. Nearly 37 billion video views occurred during the month, with Google Sites generating the highest number at 15.7 billion, followed by Hulu with 1 billion and Yahoo Sites with 815 million. ComScore’s March 2012 YouTube partner data revealed that video music channels VEVO -- 49.1 million viewers -- and Warner Music -- 30.3 million viewers -- maintained the top two positions. Gaming channel Machinima ranked third with 22.9 million viewers, followed by Maker Studios with 14.6 million, FullScreen with 12 million and BroadbandTV with 8.5 million. Among the top 10 YouTube partners, Machinima demonstrated the highest engagement -- 69 minutes per viewer -- followed by VEVO at 62.5 minutes per viewer. VEVO streamed the most videos -- 670 million -- followed by Machinima at 379 million. Also of note during March, 83.5 percent of the U.S. Internet audience viewed online video, while the duration of the average online content video was 6.4 minutes, and the average online video ad was 0.4 minutes. Video ads accounted for 18.5% of all videos viewed, and 1.5% of all minutes spent viewing video online.