Make Reddit Great Again: Assessing Community Effects of Moderation Interventions on r/The_Donald

The subreddit r/The_Donald was repeatedly denounced as a toxic and misbehaving online community, reasons for which it faced a sequence of increasingly constraining moderation interventions by Reddit administrators. It was quarantined in June 2019, restricted in February 2020, and finally banned in June 2020, but despite precursory work on the matter, the effects of this sequence of interventions are still unclear. In this work, we follow a multidimensional causal inference approach to study data containing more than 15M posts made in a time frame of 2 years, to examine the effects of such interventions within and without the subreddit. We find that the interventions had strong positive effects toward reducing the activity of problematic users both inside and outside of r/The_Donald. However, the interventions also caused an increase in toxicity and led users to share more polarized and less factual news. Additional findings of our study are that the restriction had stronger effects than the quarantine and that core users of r/The_Donald suffered stronger effects than the other users. Overall, our results provide evidence that the interventions had mixed effects and paint a nuanced picture of the consequences of community-level moderation strategies. We conclude by reflecting on the challenges of policing online platforms and by discussing implications for the design and deployment of moderation interventions.