Introduction
Introduction
Social media, including Facebook, Twitter and YouTube, have become major battlegrounds in this year's elections. Candidates are using the platforms to identify and organize supporters and raise funds. They bypass traditional news media to send their messages unfiltered to the public. They target niche audiences with growing precision, contact hard-to-reach voters, extend their influence as online supporters forward their messages and carry out many campaign tasks at much lower cost than before. The increasing ability of campaign strategists to collect and analyze information about individual voters has raised privacy concerns, and many worry that the social networks' insular nature contributes to political polarization. But social media's low cost, ease of use and wide reach also raise hopes that they can level the campaign-spending playing field.