News Feature: The genuine problem of fake news.

In 2010 computer scientist Filippo Menczer heard a conference talk about some phony news reports that had gone viral during a special Senate election in Massachusetts. “I was struck,” saysMenczer. He and his team at IndianaUniversity Bloomington had been tracking early forms of spam since 2005, looking mainly at then-new social bookmarking sites such as https://del. icio.us/. “We called it social spam,” he says. “People were creating social sites with junk on them, and getting money from the ads.” But outright fakery was something new. And he remembers thinking to himself, “this can’t be an isolated case.” Of course, it wasn’t. By 2014 Menczer and other social media watchers were seeing not just fake political headlines but phony horror stories about immigrants carrying the Ebola virus. “Some politicians wanted to close the airports,” he says, “and I think a lot of that was motivated by the efforts to sow panic.” By the 2016 US presidential election, the trickle had become a tsunami. Social spam had evolved into “political clickbait”: fabricated money-making posts that lured millions of Facebook, Twitter, and YouTube users into sharing provocative lies—among them headlines claiming that Democratic candidate Hillary Clinton once sold weapons to the Islamic State, that Pope Francis had endorsed Republican candidate Donald Trump, and (from the same source on the same day) that the Pope had endorsed Clinton. Socialmedia userswere also being targeted by Russian dysinformatyea: phony stories and advertisements