I believe more and more people will escape to lemmy sooner or later, and I already see 3 different communities for the same thing (selfhosted) here on lemmy. Time will tell which one will be the most active, but lets assume all of them will be equally active and the desire emerges to combine the two communities about the same thing, is that something possible or intended to be possible with federated services?
I don’t know how Lemmy or Kbin work internally, but I believe merging 2 communities could be similar to a user migrating to another server. Account migration on the Fediverse works by having the old account being setup as a pointer to the new account, effectively merging the old one into the new one. Followers of the old account will automatically follow the new account.
Since Lemmy and Kbin’s communities are, behind the scene, like user accounts boosting messages posted in them, you can see how a community could be marked as “migrating” into the new one.
Another option would be for a community A to automatically boost/repost all posts from a community B, effectively bringing all messages of B into A.
Note that these are pure speculation on my part. I don’t know if any of this is possible 😅
Yeah, I don’t know anything about the actual ActivityPub protocol, but having communities point to each other seems like a way of not only combining communities, but also letting sub-communities within them merge and fork as they see fit.