Reddit, a social news site where members post links to material they find interesting. If others agree, a post is voted up -- and likewise, unworthy posts can be voted down. Links that receive community approval, bubble up to Reddit's front page -- a coveted spot that Reddit users seek.
AMA is one of the specialized communication tools on Reddit. Members, known as Redditors, can submit a request to host an AMA themselves, and they can suggest the name of someone they'd like to hear from. An AMA is a real-time dialogue between a person of note and Redditors.
While Obama is not the first celebrity or politician to use Reddit, he is arguably the most famous person to do so. Past celebrity AMA participants include Jimmy Kimmel, Stephen Colbert, Larry King and astrophysicist Neil Degrasse Tyson. Ron Paul hosted an AMA in 2009. The most popular "Ask me Anything" chats may garner a million page views over the course of a month, Obama's AMA got more than 2.5 million on the first day, according to Reddit.
Each post in an AMA thread -- questions, answers and comments -- is subject to the same community voting system as news links, as is the AMA itself. Obama's AMA received more than 400,000 votes, which were equally split between "up" votes and "down" votes. Currently, Obama's AMA is ranked fifth on Reddit's list of top AMAs.
But consistent with the democratic nature of Reddit, AMAs are not just for celebrities or the otherwise famous. In fact, any Redditor can submit a request for an AMA, which is then subject to the voting up and down process to determine whether the request is granted. For instance, a bored pharmacist, a curios 7-year-old and a retired cat burglar have hosted sessions.
However, there are rules. "Your day, your girlfriend, being bored or drunk, as well as your opinion on something will not be considered," according to Reddit's guidelines. Rather your AMA should be about something uncommon that plays a central role in your life.
But be forewarned, there are an awful lot of AMAs that involve adult performers and other topics that aren't appropriate for kids.