Are social media giants doing enough to prevent the spread of misinformation?

Social media has revolutionized the way we connect and communicate -- and certainly not all for the better. In his new book, "Antisocial: Online Extremists, Techno-Utopians, and the Hijacking of the American Conversation," Andrew Marantz explores how digital platforms full of unforeseen vulnerabilities have been exploited by racists and vandals. William Brangham sits down with Marantz to discuss.