For example, say an instance C is not defederated with B nor A. Can a user on A see users from B if they visit a community on C? If so, to what extent can the users from A and B interact with each other on C?
My understanding is that the “host” instance of the community is responsible in sending things out to the subscribers. As such, when users from B post on a community on C, C will broadcast the activity of user from B to instance A’s federated copy of community on C, and users on A will see the post from the user from B. They should also be able reply to each other’s comments on the community on C.
From practical example:
I defederated one instance. Before, I saw content of them, now I dont. I dont know if they can see my content but I dont think they do.
Obviously a sample size of one is not evidence but more of a hint at what might happen.
You can always ask the folks on .ml for they make the software.
