Permanent link to MTA daily media news@BarackObama Updates His Twitter! (by Adam Ostrow at Mashable) Barack Obama, Twitter’s second most popular user (CNN has passed him), updated his Twitter account [Wednesday] for the first time since taking office. The update is to promote the President’s online town hall, which encourages citizens to submit questions via The White House website. Obama will be responding to some of the most popular questions – determined by users voting them up ala Digg – via