Once again, Google sites, primarily YouTube, easily bested all other online video services in February, research firm ComScore revealed today in its Video Metrix study.

Over 169 million people watched online video in the U.S. last month, tallying over 5 billion viewing sessions. A total of 82.5 percent of the entire American Internet audience watched at least one video on the Web last month.

Not surprisingly, the vast majority of those people--over 141 million--watched video content on Google sites for a total of 1.8 billion viewing sessions. Microsoft's video services came in second behind Google with nearly 49 million unique viewers. Those folks tallied just 297.7 million viewing sessions on the month. Yahoo sites rounded out the top three with 46.7 million unique users totaling 200 million viewing sessions in February.

Facebook saw a notable uptick in viewing in February. The social network, which secured the fourth spot last month, saw over 46 million viewers enter into 170 million viewing sessions. In January, Facebook had 42 million people sit through over 122 million viewing sessions. Vevo, which came in second in January video rankings with 51 million users and over 121 million viewing sessions, dropped to fifth last month with only 45.9 million viewers. However, its viewing sessions nearly doubled to 222 million in February, ComScore found.

With all that video they're watching, Americans were destined to watch ads last month. According to ComScore, over 3.8 billion ads were served up in February for a total of more than 1.6 billion minutes. The average viewer watched 30 ads on the month.

In terms of total ads, no other provider could beat Hulu. The company served over 1.1 billion ads in February for a total of 454 million minutes. The average Hulu viewer watched 48 commercials.