This year will surely be looked back on as a turning-point moment for Twitter. The social network and micro-broadcasting service has become significant for reasons political, personal, and professional. To wrap up the year, Twitter has produced a retrospective microsite that tells the story of 2012 in Tweets, from Obama to the Pope, the Olympics to the Super Bowl, Justin Bieber to Superstorm Sandy. Check it all out at 2012.twitter.com.