  Fake news emerged as an apparent global problem during the 2016 U.S.
Presidential election. Addressing it requires a multidisciplinary effort to
define the nature and extent of the problem, detect fake news in real time, and
mitigate its potentially harmful effects. This will require a better
understanding of how the Internet spreads content, how people process news, and
how the two interact. We review the state of knowledge in these areas and
discuss two broad potential mitigation strategies: better enabling individuals
to identify fake news, and intervention within the platforms to reduce the
attention given to fake news. The cooperation of Internet platforms (especially
Facebook, Google, and Twitter) with researchers will be critical to
understanding the scale of the issue and the effectiveness of possible
interventions.
