A tweet sent from Obama's official account on election night with the words "Four more years" and a photo of the president and first lady hugging is both the most popular tweet of 2012 and the most popular tweet in Twitter history, measured by re-tweets. 

The tweet came minutes after networks called the 2012 race for Obama. 

The tweet has been re-tweeted 816,927 times since election night, a Twitter record. According to Twitter, re-tweets of Obama's reelection message came from people in more than 200 countries around the world.

Obama's tweet beats the runner-up, from Bieber. The singer's tweet, a farewell to a fan with cancer, earned 224,051 re-tweets.

Twitter also released a list of the 10 most popular political trends of the year, which include the official hashtags tracking both political conventions:

mitt romney