initially all 3 are interconnected or "federated with each other" - any member of any instance can see the communities and users from any other instance.

Suddenly something happens that makes instance A defederate with instance B

So now instance A cannot see and participate with the communities and users of B and vice versa. However instance C can see and participate in the communities of Both

So in terms of beehaw vs lemmy.world I would be on instance 3 - I can see and participate both, their defederation from each other doesn't affect you, it only affects the users of beehaw or Lemmy.world

EDIT:

I just realised your in lemmy.world. huh weird... Maybe it takes a while for the defederation to settle, or maybe it makes it a one way communication.

EDIT2 I might be wrong, see this post

lemmyworld@lemmy.world/t/22361/-/comment/96933

[–] NotInTheFace@lemmy.world 5 points 1 year ago (1 children)

Can't open that link, I don't have Kbin.

[–] Da_Boom@iusearchlinux.fyi 1 points 1 year ago* (last edited 1 year ago)

Neither do I. And I created that link.

Edit: huh that's weird, I could access it before.

It's actually a link to a comment in this post, for some reason jerboa gave me a kbin link. I've removiing the kbin part. And reformatting it

Edit: ok so I need to work out how to translate these links coz that didn't work

Essentially it was about the fediverse using a "push" model, meaning instances push their comments to other instances. It means you can see the community and posts, but if you comment on it, it won't get pushed to the instance that hosts the community - only people from your instance will see the comments and posts

If a community defederates, it essentially blocks the push, preventing it from reaching the community.

[–] edgerunneralexis@dataterm.digital 3 points 1 year ago

So in terms of beehaw vs lemmy.world I would be on instance 3 - I can see and participate both, their defederation from each other doesn't affect you, it only affects the users of beehaw or Lemmy.world

This aspect is really crucial for people to understand, so I wanted to emphasize it. This is what gives the Fediverse it's hyper free nature, where if you don't like which instances your instance has chosen tp block, you can always switch to a third instance and have access to both your old instance (thus solving the network effect) and the new one (thus giving you freedom of association). This sort of connected-by-default design choice (I.e. using blacklists instead of whitelists) is also crucial for maintaining the general interconnectivity of the network thats crucial to its functioning.