US president appears on social news site Reddit

US President Barack Obama has spent 30 minutes answering questions from members of social news site Reddit.

President Obama's appearance was a surprise and during the Q&A session he answered 10 questions from the tens of thousands submitted.

He responded to queries about political financing, troops in Afghanistan and net legislation.

The chat proved so popular with Redditors, it made the whole site slow to respond.

Many commentators said Obama's appearance was a coup for Reddit and the chat would help its march towards mainstream influence alongside other social media sites such as Twitter and Facebook.

Barack Obama has a long history of using social media both to support his candidacy before being elected and while serving as president. In July 2011 he held a "town hall" meeting via Twitter, in which he answered vetted questions submitted via the micro-blogging site.

The timing of the Reddit chat was seen to be significant as it coincided with the US Republican Party convention. This meant chatter on Twitter about issues at the convention was jostling for attention with tweets about Obama's Reddit chat.

Erik Martin, general manager of Reddit, told The Verge the chat had been set up for a while but kept secret to remain "true to the spirit" of other Q&A sessions on the site.

Such sessions, known as AMAs (Ask Me Anything), can be rough for those answering questions, if they are judged by Reddit members to be ducking controversial issues.

Despite the president not answering questions about drug legalisation and other controversial subjects, the response by Redditors to his appearance was largely positive. The reaction was helped by the president signing off from the chat by referencing an image-based Reddit meme that features himself.

Alexis Madrigal at The Atlantic likened the chat to a "factory tour" because it did nothing to elicit anything substantive from Mr Obama. Despite this, he said, the chat was significant because it showed social media could remove the layers that often separated politicians from people.

"Sure, it was the novelty," he wrote, "but the novelty portends other things."