2012 was a good year for social media. With more than 1 billion active monthly users on Facebook, more than 175 million tweets per day, more than 104 million visits per month to Pinterest, and more than 4 billion hours of video watched on YouTube each month, social media is exploding. Well, really, it has exploded.

All of these platforms have launched specific opportunities for brands to engage: Facebook brand pages, Twitter verified accounts and promoted campaigns, Pinterest's newly launched business accounts, and YouTube's brand channels.
Of course, just because the opportunity exists doesn't mean that all brands use these platforms to their full potential. However, there have been a select few who have blown it out of the park this past year.
Here's a rundown of what I consider the best social media campaigns of 2012. What would you add to the list?