From the presidential race to the battle for the office of New York City mayor, American political candidates' approach to new media strategy is increasingly what makes or breaks their campaign. Targeted outreach on Facebook and Twitter, placement of a well-timed viral ad, and the ability to roll with the memes, flame wars, and downvotes that might spring from ordinary citizens' engagement with the issues--these skills are heralded as crucial for anyone hoping to get their views heard in a chaotic election cycle. But just how effective are the kinds of media strategies that American...