We'll leave it up to the cultural anthropologists of the future to unravel the significance of the fact that Rebecca Black's "Friday" was the most watched video on YouTube in 2011. Just a brief look at the basic statistics of YouTube's viewership this year, however, clearly shows how much of a force Google's video sharing site has become. According to YouTube's own data, the site saw more than one trillion (1,000,000,000,000) playbacks this year. That's an astonishing 140 views for every person on earth, or, as Google puts it, "more than twice as many stars as in the Milky Way."

Last year, the "Bed Intruder Song" took the top billing in YouTube's annual top 10 list. This year, it was Rebecca Black's "Friday." While there wasn't a single cat video in last year's top 10, this year saw two of them make the list ("Nyan Cat" and "cat mom hugs baby kitten"). Sadly, my favorite cat video of the year didn't make the list, though.

Here is the complete top 10: