You cannot defederate from a “community”, but you can have your specific user account block either a community or an entire instance (to varying degrees of effectiveness - you can still see posts from people on those instances, and chat with them, but you won’t receive “notifications” from them anymore).
Defederation from an “instance” is meant as a last-resort effort to avoid an enormous amount of moderation work, like if it keeps sending child porn across the Fediverse, or users are overwhelmingly harassing others or something.
Here, you can read about such occurrences directly from the sources involved (who chose to do it) like https://hexbear.net/post/1712067, and then various responses in return like https://programming.dev/post/2652745 (tldr: hexbear defederated from them, so they defederated in return to avoid people getting confused from one-sided conversations where messages could be sent but never received) and https://lemm.ee/comment/2155764 etc.
And yes, you are stuck at your current instance if you care about keeping your account. You can copy your rules like block list from one user account to another though, like I have an alt at StarTrek.online, which mitigates somewhat the pain of having to move. If someone were to try to send me a DM at my old one though, I would not get it at the new account - instead I would have to keep both active, forever. It turns out that the idea that you can move freely around the Fediverse was a lie - or at least, it is something that isn’t fully implemented yet. Theoretically it is something that could be done, if someone were to bother to implement that, but it hasn’t been done yet.
All of Lemmy is still beta software. It helps to lower expectations:-). It is still 1000x better than Reddit imho, b/c of (a) no ads and lack of other forms of enshittification as well (e.g. automatically playing videos that you cannot stop with a setting somewhere), (b) the people are more worth talking to here (generally speaking; except those places that tend to be defederated by the major instances, b/c of all the harassment they kept doing).
It turns out that the idea that you can move freely around the Fediverse was a lie - or at least, it is something that isn’t fully implemented yet.
I don’t think account mobility was ever an expectstion until recently, just that you could access all federated instances from any instance. I can ‘move freely’ with my account to any federated instance without needing separate logins.
iirc, it was one of the points sold to people as we migrated away from Reddit during the exodus. But I like your more precise phrasing of what it actually is.:-) More was told during the exodus though, e.g. “just as Reddit is falling, if the instance you pick likewise falls, then you can move your account to another one”, i.e. it barely matters which instance you picked at first, so just jump in and see. But different language may have been used at different times and places - e.g. the expectations of people already here vs. the newly incoming ones (like me:-).
You cannot defederate from a “community”, but you can have your specific user account block either a community or an entire instance (to varying degrees of effectiveness - you can still see posts from people on those instances, and chat with them, but you won’t receive “notifications” from them anymore).
Defederation from an “instance” is meant as a last-resort effort to avoid an enormous amount of moderation work, like if it keeps sending child porn across the Fediverse, or users are overwhelmingly harassing others or something.
Here, you can read about such occurrences directly from the sources involved (who chose to do it) like https://hexbear.net/post/1712067, and then various responses in return like https://programming.dev/post/2652745 (tldr: hexbear defederated from them, so they defederated in return to avoid people getting confused from one-sided conversations where messages could be sent but never received) and https://lemm.ee/comment/2155764 etc.
And yes, you are stuck at your current instance if you care about keeping your account. You can copy your rules like block list from one user account to another though, like I have an alt at StarTrek.online, which mitigates somewhat the pain of having to move. If someone were to try to send me a DM at my old one though, I would not get it at the new account - instead I would have to keep both active, forever. It turns out that the idea that you can move freely around the Fediverse was a lie - or at least, it is something that isn’t fully implemented yet. Theoretically it is something that could be done, if someone were to bother to implement that, but it hasn’t been done yet.
All of Lemmy is still beta software. It helps to lower expectations:-). It is still 1000x better than Reddit imho, b/c of (a) no ads and lack of other forms of enshittification as well (e.g. automatically playing videos that you cannot stop with a setting somewhere), (b) the people are more worth talking to here (generally speaking; except those places that tend to be defederated by the major instances, b/c of all the harassment they kept doing).
I don’t think account mobility was ever an expectstion until recently, just that you could access all federated instances from any instance. I can ‘move freely’ with my account to any federated instance without needing separate logins.
iirc, it was one of the points sold to people as we migrated away from Reddit during the exodus. But I like your more precise phrasing of what it actually is.:-) More was told during the exodus though, e.g. “just as Reddit is falling, if the instance you pick likewise falls, then you can move your account to another one”, i.e. it barely matters which instance you picked at first, so just jump in and see. But different language may have been used at different times and places - e.g. the expectations of people already here vs. the newly incoming ones (like me:-).