YouTube released its top trending videos of the year Tuesday, showing us that 2011 was a year of unlikely pop stars, cute kids and — of course — cats.

It was a big year for Google’s online video site, which logged a jaw-dropping 1 trillion views in 2011.

Rebecca Black’s Friday topped the list of the year’s most-viewed videos; other viral hits that made the list include the talking twin babies, Nyan Cat, Lonely Island and Nicki Minaj’s “The Creep” and Maria Aragon’s “Born This Way” cover.

According to YouTube Trends manager Kevin Allocca, the list speaks to “something that’s very core to us as a site.”

“Rebecca Black, she’s on top of the list,” Allocca said. “She had over 180 million views this year, one of things that she represents. . .is the idea that anyone can enter our pop culture,” she said.

Black’s rise from a much-maligned YouTube star to a co-star in Katy Perry’s viral hit “Last Friday Night” is entirely thanks to her online fame. Allocca pointed to Aragon, too, as an illustration of this phenomenon. “Maria Aragon, went from posting covers online to being on stage,” he said.

Another core trend on YouTube? “The classical one,” Allocca said. “Pets and babies.”

He said that videos of pets and babies tend to take off because they lower language barriers.

The talking babies video, for example, he said, has 60 million page views but only a quarter of those have been in the U.S. “It’s a rough estimate, but it’s something like 1 out every 100 people in the Philippines have seen these two babies,” he said.

And then there are the trends that are harder to explain.

Nyan Cat is really hard to describe to people, but I love that it made the list,” Allocca said. Nyan Cat, for those who don’t know, is. . .well, it’s kind of hard to explain. At face value, Nyan Cat is an animation of a cat with a Pop-Tart body flying through space to the soundtrack of a Japanese pop song. The cat leaves a rainbow trail behind it. And it has millions of hits.

Allocca said the best thing about Nyan Cat is that it’s not the video itself that made it go viral. “The web culture around the video made it, not the video itself,” he said. “There at least 1,000 versions of this thing, one for every other country, random iterations of it — there’s even a three-hour version of it,” he said.

The appeal of Nyan Cat, he theorized is partly that it’s a joke video that’s easy to replicate and participate in, and partly because the Web community is able to point to memes like that and say, “I cannot believe that we made that one of the most-viewed videos of the year.”

YouTube’s impact this year has stretched beyond absurd pop culture, too.

This is one of YouTube’s biggest-ever years for news, as the world witnessed some of the biggest news stories through the lenses of cellphone cameras.

The Arab Spring movements, tsunami and earthquake in Japan and the tornados that ripped through Missouri were all recorded through first-person accounts put up on YouTube.

“When I think about what made the most impact on me, those are a couple of moments that I’ll remember,” Allocca said.

The site is also gearing up for a big campaign season after a year of viral ads and trail moments such as the Herman Cain ad that featured his campaign manager lighting up a cigarette or Rick Perry’s “oops” moment in a Republican debate.

Allocca said the year ahead will see much more political content such as parodies or advocacy videos.

He also said that he believes YouTube’s recently madeover video channels will be a bigger part of Internet trends.

“Right now we talk a lot about individual videos, but just for a little bit of comparison, you have someone like [comedian] Ray William Johnson, who has three channels with a billion views,” he said.

Viral video is cross-generational, he said, which is why it gets passed around inboxes and social networks, but he believes channels will become “more and more a part of our user experience every day” in the year ahead.

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