A paper co-authored by Gareth Tyson and Ignacio Castro, “Open or Blocked Skies? Community Moderation Practices in Bluesky,” has been presented at The ACM Web Conference 2026.
The paper presents a large-scale study of Bluesky’s community-driven blocking mechanisms, examining who gets blocked, what behaviours blocklists target, and how blocking affects users’ visibility, activity and social connections. We find that community blocking operates at a scale far beyond official platform moderation and affects the visibility of more than 90% of Bluesky content. Blocked accounts also tend to be among the platform’s most active, popular, toxic and politically engaged users, although being blocked has relatively limited effects on their subsequent activity or position in the social graph.
The work was carried out by Saidu Sokoto, Leonhard Balduf, Onur Ascigil, Gareth Tyson, Ignacio Castro, Björn Scheuermann, Andrea Baronchelli and Michał Król.