Barack Obama has won a second term . Giving an eloquent victory speech in front of his supporters in Chicago, the president paid tribute to his rival, Mitt Romney, and, with it, put the most expensive presidential election to bed. As of this writing, his tweet of "Four more years " had been retweeted over half a million times, as well as being reinterpreted  in a variety of ways. At the height of last night's Twittersphere frenzy, over 300,000 tweets were being sent per minute, the firm revealed . In fact, this was the most tweeted political event  in the country's history.
So what made the Obama campaign triumph? It was a mixture of feet on the ground  and a very sophisticated donation system  that sourced smaller donations from the many, rather than Howitzer-sized piles  from the few.
Elsewhere, Democrats retained control of the Senate, and the House remained Republican.