Do Platform Migrations Compromise Content Moderation? Evidence from r/The_Donald and r/Incels

Moderation reduces activity
but at the expense of
radicalizing migrated users.

Best Paper Honorable Mention Award

Manoel Horta Ribeiro, Shagun Jhaver, Savvas Zannettou, Jeremy Blackburn, Gianluca Stringhini, Emiliano De Cristofaro, and Robert West, “Do Platform Migrations Compromise Content Moderation? Evidence from r/The_Donald and r/Incels,” Proc. ACM Hum.-Comput. Interact. 5, CSCW2, Article 316 (October 2021), 24 pages, DOI: 10.1145/3476057

Media coverage


When toxic online communities on mainstream platforms face moderation measures, such as bans, they may migrate to other platforms with laxer policies or set up their own dedicated websites. Previous work suggests that within mainstream platforms, community-level moderation is effective in mitigating the harm caused by the moderated communities. It is, however, unclear whether these results also hold when considering the broader Web ecosystem. Do toxic communities continue to grow in terms of their user base and activity on the new platforms? Do their members become more toxic and ideologically radicalized? In this paper, we report the results of a large-scale observational study of how problematic online communities progress following community-level moderation measures. We analyze data from r/The_Donald and r/Incels, two communities that were banned from Reddit and subsequently migrated to their own standalone websites. Our results suggest that, in both cases, moderation measures significantly decreased posting activity on the new platform, reducing the number of posts, active users, and newcomers. In spite of that, users in one of the studied communities (r/The_Donald) showed increases in signals associated with toxicity and radicalization, which justifies concerns that the reduction in activity may come at the expense of a more toxic and radical community. Overall, our results paint a nuanced portrait of the consequences of community-level moderation and can inform their design and deployment.

BibTeX citation

    author = {Horta Ribeiro, Manoel and Jhaver, Shagun and Zannettou, Savvas and Blackburn, Jeremy and Stringhini, Gianluca and De Cristofaro, Emiliano and West, Robert},
    title = {Do Platform Migrations Compromise Content Moderation? Evidence from r/The_Donald and r/Incels},
    year = {2021},
    issue_date = {October 2021},
    publisher = {Association for Computing Machinery},
    address = {New York, NY, USA},
    volume = {5},
    number = {CSCW2},
    url = {},
    doi = {10.1145/3476057},
    journal = {Proc. ACM Hum.-Comput. Interact.},
    month = {oct},
    articleno = {316},
    numpages = {24},