That's exactly what I thought of. Here's my proposal (though I don't know if this can be implemented in the technology or if it would be compatible with ActivityPub):
Suppose we have two similar communities (i.e., north.pole and north.star, but they both tackle northness but in different instances). The mod from either communities would send an invite to the other to form a "group" or "federate" or "ally". Now, if the other mod approves, here's what happens:
Whenever you post something in a community that has a group, it would be synced with the communities in other instances that are allied to it, including upvotes, comments, and other metrics. So if I post in north.pole, people in north.star could see my post too because we're in an "alliance" and vice versa. They can also upvote my post and I can upvote theirs. There would just be a sign (probably a flair-like design) that would tell users in other instances from which instance the post came from.
With regards to moderation, here's how: they are basically separate communities with content syncing between them. Suppose a user in north.star posts something offensive and against north.pole community rules. The mods in north.pole can block that post from appearing in the north.pole feed.
And here's an unrelated gripe: there should be an instance-standard "ouster poll" for communities that are dead. With what I see right now in the influx of Lemmy users, many communities are dead and users are willing to revive them but they can't because the moderators of those communities are already inactive and redundancy is a pain in "advertising" membership in Lemmy already. There should be like a poll of interested users where they would agree to "oust" the inactive mod (of course there's also a qualification for "inactive") and replace them with probably a democratically "elected" moderator.
Tell us, what is missing for you?
Niche anime communities. So far, it's just Bocchi the Rock that has a separate community from the Anime community in lemmy.ml. I need my Re:Zero, KonoSuba, Kaguya-Sama, Classroom of the Elite, Call of the Night etc. I hope with more people coming in, it would been the flourishing of an entire anime ecosystem here in Reddit (probably one instance for anime solely?)
I have a shower thought earlier about this: what if there was a feature exclusive to community mods that allows communities similar to theirs to form a group?
Now what would the group do? Communities that are members of those groups basically would share data with each other and sync posts between each other. Community mods could send invites to similar communities on other instances to form a group. Say for example, technology@beehaw.org and technology@lemny.ml are in one group. Now if I post in Beehaw's technology community, it would also appear in Lemmy.ml's technology community because they are in the same group (probably with a flair-like feature that would indicate the instance from where the post comes from). Upvotes and comments will also be synced between the communities as well.
Now, what about moderation? The community mods in the respective instances still have power over what the community sees and if it obeys the community rules. Community mods could filter what posts would appear in their community's version. So if, for example, a person from lemmy.ml's technology community were to post something that goes against beehaw's tech community rules, the mods from Beehaw can block that post from appearing in the Beehaw tech community. It would not affect the Lemmy.ml community though. In this way, it preserves the decentralization of the fediverse while at the same time, making it intuitive for users too because they don't have to switch between similar communities because they can stay on their instances and still get content from the other instances with similar topics.
Okay, so you only need one account to access the entire fediverse network, may it be Kbin or Lemmy (even Mastodon can actually access the fediverse). So you don't need a separate account for Lemmy when you already have a Kbin account because you can access the same content as any other Lemming (that's what the folks down below said users of Lemmy are) there is.
Magazines are to Kbin as subreddits are to Reddit and communities are to Lemmy
You missed the bleep-bloop!