Open or Blocked Skies? Community Moderation Practices in Bluesky
Sokoto, S., Badhuf, L., Ascigil, O. , Tyson, G., Castro, I., Scheuermann, B., Baronchelli, A.
ORCID: 0000-0002-0255-0829 & Krol, M.
ORCID: 0000-0002-3437-8621 (2026).
Open or Blocked Skies? Community Moderation Practices in Bluesky.
Paper presented at the ACM The Web Conference, 13-17 Apr 2026, Dubai, United Arab Emirates.
doi: 10.1145/3774904.3792106
Abstract
Content moderation is a major challenge for online platforms. While user-driven blocking is a common tool, its dynamics are usually hidden as moderation data is private. Bluesky makes moderation actions public-by-design, providing an unprecedented opportunity to study a community-driven moderation ecosystem at scale. We leverage this transparency to (1) map the ecosystem of moderation blocking actions across 34 million users, including both individual blocks and the through blocklists, (2) identify the signals that correlate with blocking, and (3) measure the consequences of these actions. We demonstrate that community blocking is widespread, with a volume several orders of magnitude higher than official takedowns, and affects the visibility of more than 90% of Bluesky content. The blocked accounts represent the most active, popular, toxic, and politically inclined users. However, different blocklists target different types of accounts and behaviors. Finally, blocking does not decrease the popularity and activity of the blocked users and has a limited effect on the social graph. By quantifying its dynamics and trade-offs, our study provides empirical grounding for designing future moderation systems that are transparent, pluralistic, and resistant to centralized control. Taken together, this study provides the first large-scale, quantitative analysis of a community- driven moderation ecosystem, demonstrating how individual and collective interventions influence user behavior.
| Publication Type: | Conference or Workshop Item (Paper) |
|---|---|
| Additional Information: | This work is licensed under a Creative Commons Attribution 4.0 International License. |
| Publisher Keywords: | Bluesky, User-driven moderation, Community moderation, Community blocklists, Decentralized social networks |
| Subjects: | H Social Sciences > H Social Sciences (General) Q Science > QA Mathematics > QA75 Electronic computers. Computer science |
| Departments: | School of Science & Technology School of Science & Technology > Department of Computer Science |
| SWORD Depositor: |
Available under License Creative Commons Attribution.
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