About an hour ago, President Barack Obama signed on to the social media website Reddit and stumped for users' votes.

In a post titled "Reddit, this is important," Obama told redditors that "polls will start closing in this election in just a few hours, and I need you to vote."

Like one of the gang, the president dutifully sat for an AMA (that's "Ask Me Anything"), a post where a famous or otherwise interesting person answers questions from users. It was the most popular AMA in Reddit's history.

Reddit's user base is primarily liberal, male 20-somethings, a group that will be especially important today. The youth vote helped Obama carry at least three swing states in 2008 and he is trying to rekindle their enthusiasm this time around, since it appears to have waned.

Obama ended his foray into the social networking site with a savvy nod to Reddit culture. He wrote: "If you've voted already, don't stop there—spread the word to your friends, roommates, and neighbors. Think of it as upvoting."

(Note: "Upvoting" is when one user agrees with another user's post, increasing its rank on a page.)

Image via Reddit