Last week, Beehaw.org announced that they are de-federating themselves from Lemmy.world and sh.itjust.works. All three of those Lemmy instances are big, with dozens of very active, popular communities. So how does that impact you as a Lemmy user?
When Beehaw.org says they are "de-federating" with Lemmy.world and sh.itjust.works, what they mean is that they've blocked Lemmy.world and sh.itjust.works from participating in communities on beehaw.org. That means that users who registered accounts at lemmy.world and sh.itjust.works won't be able to participate on any communities at beehaw.
If you're a user who registered at a different Lemmy instance, such as our own Lemmy.ninja, you won't be affected. You will still be able to participate in communities from all three of those instances.
There's another impact, however. Sh.itjust.works and (especially) Lemmy.world are sites with a large number of users. By defederating, Beehaw has eliminated a large number of users from participating in their communities. That means that the communities at Beehaw will become less active, and competing communities on other instances may start to grow.
Excellent write-up on the matter.
The key to a successful fediverse is always decentralization. The more communities there are on more instances, the less damage any one can do by defederating others, defederating themselves, or shutting down, and the more likely people are to find communities that work for them.
It's entirely beehaw's choice to defederate from a couple of the biggest instances. That's the benefit of having individual communities, after all. It could make their users happier even. Then other groups will be happier continuing to federate.