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?
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?
except instance A will actively reject such content from B users when it hears about it from C.
generally it should be expected not to see any new content from B, but historic content will still exist and basically be in a frozen state.