A 2018 journal article entitled “Exposure to Extremist Online Content Could Lead to Violent Radicalization: A Systematic Review of Empirical Evidence” scanned the content of more than 5,000 previous studies, but found that only 11 included “tentative evidence that exposure to radical violent online material is associated with extremist online and offline attitudes, as well as the risk of committing political violence among white supremacist, neo-Nazi, and radical Islamist groups.” The authors acknowledged that they could not conduct a systematic meta-analysis “due to the heterogeneous and at times incomparable nature of the data.” To the extent generalizations were possible, the authors reported that “active seekers of violent radical material [appear] to be at higher risk of engaging in political violence as compared to passive seekers.” If that is the case, then preventing extremist content from being published on large-scale social-media platforms is unlikely to be highly effective, as it is primarily being consumed by those who already have committed to its message.