"But the Obama team had a solution in place: a Facebook application that will transform the way campaigns are conducted in the future. For supporters, the app appeared to be just another way to digitally connect to the campaign.... That’s because the more than 1 million Obama backers who signed up for the app gave the campaign permission to look at their Facebook friend lists. In an instant, the campaign had a way to see the hidden young voters. Roughly 85% of those without a listed phone number could be found in the uploaded friend lists....in those final weeks of the campaign, the team blitzed the supporters who had signed up for the app with requests to share specific online content with specific friends simply by clicking a button."
http://swampland.time.com/2012/11/20/friended-how-the-obama-...