" Do musical preferences predict political inclinations? Not long ago, an official with Pandora said that its predictions about those inclinations, based on zip code as well as musical choices, are between 75 and 80 percent accurate. And with that level of accuracy, it developed an advertising service “that would enable candidates and political organizations to target the majority of its 73 million active monthly Pandora listeners based on its sense of their political leanings. "

― Cass R. Sunstein , #republic: Divided Democracy in the Age of Social Media