Happy Birthday, YouTube Trends. Today marks the one-year anniversary of our launch and what better way to celebrate than to look at some of the trends behind the Trends.

In 2011, we featured over 2,000 Trending videos which went on to be seen over 5 billion times. Those videos were spread pretty evenly between all our categories with Music, Comedy, News, Sports, and Entertainment among the most popular.

And now it's time for YouTube Trends most-viewed posts of ALL-TIME:

1. Top 10 Most Shared Videos of 2010
   
   
2. Rick Perry’s 'Oops': The Morning After on YouTube
   
   
3. Why Rebecca Black Might Be Around Longer Than Other Viral Stars
   
   
4. What Will the Biggest March Trend Be?
   
   
5. Top 10 'People' Videos of 2010
   
   
6. Charlie Sheen 'Winning' YouTube
   
   
7. Osama bin Laden News Draws YouTube Reaction from Across the Country
   
   
8. Rebecca Black Hits 100 Million Views
   
   
9. The 10 Most Viewed Flash Mobs of All Time
   
   
10. South Korea's Susan Boyle?

Honorable Mention goes to 'Cone-ing' or: How to Will a Trend into Popularity.

And remember...