comScore Publishes December 2011 U.S. Online Video Rankings; Facebook Slips

Audience measurement firm comScore has just released its U.S. online video rankings for December 2011. There are few surprises: Google’s YouTube is still king of the hill, while VEVO remains firmly in second place with roughly a third of Google Sites’ audience.

In total, comScore says 182 million U.S. users watched online video content in December 2011 for an average of 23.2 hours per viewer. The total U.S. Internet audience viewed 43.5 billion videos.

What caught my eye, however, was that Facebook dropped from third place in November 2011 to fifth place, trailing Yahoo and Viacom properties again, in a single month.

According to comScore’s data, almost 50.8 million unique viewers watched online videos on in November 2011. The month after that, only a little over 42 million people did.

The number of videos watched by these people also dropped significantly: from roughly 270 million in November 2011 to close to 240 million in December 2011.

Looking at the data from October 2011, the drop becomes even more noteworthy: that month Facebook had bumped VEVO off #2 with almost 60 million viewers watching 346 million videos.

That’s a loss of 18 million unique viewers in two months for online video content posted on I’m struggling to find an explanation for this, and comScore did not offer one either.

Care to venture a guess?