If you’re asking about moderation, it works similarly as you’d expect it to work in a everything-RSS world.
At the hosting level, the hosting you use will likely ban you for clearly illegal stuff. Same as blogspot dot com or Cloudflare could ban you for certain things.
At the application level, application admins/mods would moderate as any app does. This is similar to running any web service today with user generated content. It’s up to app developers to choose. Apps can also provide primitives for userland moderation, like Reddit does, or even ability to plug your own extra moderation services (which Bluesky allows). But again, this is largely how it works on any app with user-generated content.
There’s no “defederation” because there’s no analog of “community instances” that may fight with each other. There’s hosting, there’s apps, and there’s app-level moderation that works according to each app’s developer’s choices.
Does this help clarify it?
> Apps can also provide primitives for userland moderation, like Reddit does, or even ability to plug your own extra moderation services (which Bluesky allows).
This is the part I would be looking for, in an article talking about "there are no instances". Is there a standard protocol for this, so that anyone can spin up a shared moderation service that people can subscribe to if they're aligned with it, and be able to plug that into any standard app built on the protocol (not just Bluesky-the-company's app)? Or is this something specific to Bluesky-the-company?
If this is a standardized part of the protocol, then that answers the question of "how does ATProto solve the same problems defederation solves".
There are several other things I can think of in the category of "how do you solve the problems that ActivityPub uses instances to solve", but they're things I've already asked in other parts of this thread, namely "how do you make the parts of the system not shown in the tidy hosts->apps M:N graph decentralized, too".
Great questions! The protocol does have suggested app-agnostic moderation primitives (see https://atproto.com/guides/labels, https://atproto.com/guides/creating-a-labeler). That's the basis of how Bluesky's own moderation works under the hood. There's also Bluesky-specific tools and APIs like Ozone (https://atproto.com/guides/using-ozone), but they build on top of those primitives.
Of course, nothing stops an app from doing moderation differently and not using any of that. This is more for better composability and interoperability.