Over the past few years, concerns about the
negative societal consequences of the spread of misinformation have become widespread. While false news and propaganda are far from being a new phenomenon, the emergence and popularization of social networking platforms appear to have increased the prevalence of false news stories and the speed at which they become viral. False rumors and news stories that were spread on social media have been mentioned as one of the reasons for the recent rise of populist candidates in the U.S. and Europe and as fuel inciting violence against ethnic minorities in countries such as Sri Lanka and Myanmar (see e.g. Taub and Fisher, 2018). The same new technology tools that allowed the pro-democracy groups during the Arab Spring to coordinate and start a revolution are now seemingly giving a platform to conspiracy theorists and extremist actors seeking to manipulate the political agenda in their own financial or political interest. However, we still know relatively little about the extent to which false news are indeed widespread on social media and the extent to which they have a causal effect on individual attitude change or offline violence. This short note offers an overview of the existing empirical evidence regarding the prevalence of misinformation on social media sites and different individual- and contextual-level factors that may explain its diffusion.