Threads has begun testing federation over ActivityPub. And they have blocked two important servers I administrate. The first server is the Mostr Bridge. The Mostr Bridge connects ActivityPub and Nostr together, so people can communicate across protocols. The second server is Spinster.xyz, which is arguably the largest independent feminist community online.
[citation needed]
The fedi is, in fact, full of illegal content, but good admins share the blocklists so that nobody has to see it.
Tells you a lot about the Pleroma admins that insist on remaining completely unmoderated.
This is a good start: https://cyber.fsi.stanford.edu/io/news/addressing-child-exploitation-federated-social-media