  In the current landscape of online abuses and harms, effective content
moderation is necessary to cultivate safe and inclusive online spaces. Yet, the
effectiveness of many moderation interventions is still unclear. Here, we
assess the effectiveness of The Great Ban, a massive deplatforming operation
that affected nearly 2,000 communities on Reddit. By analyzing 16M comments
posted by 17K users during 14 months, we provide nuanced results on the
effects, both desired and otherwise, of the ban. Among our main findings is
that 15.6% of the affected users left Reddit and that those who remained
reduced their toxicity by 6.6% on average. The ban also caused 5% users to
increase their toxicity by more than 70% of their pre-ban level. Overall, our
multifaceted results provide new insights into the efficacy of deplatforming.
As such, our findings can inform the development of future moderation
interventions and the policing of online platforms.
