Lemmy

So... multi-communities (mc) that can include multi-communities?

If you wanted to get more fine-grained to allow filtering of busy communities (c ), you could add tags (t) to posts so they would be contextual (it would be able to distinguish between rock music and rocks, for example) and could then also be added into multi-communities.

So if you were interested in dinosaurs, you could have an /mc/EarthSciences that contains /mc/Geology, /mc/Meteorology and /mc/Palaeontology and inside the last one you might have /mc/Dinosaurs which might include a few /c/Dinosaurs as well as /t/Dinosaurs, the latter scooping everything else up. /mc/Dinosaurs may also contain /mc/Velociraptors, /mc/TRex, /mc/Spinosaurus, etc, etc.

It would be easy enough to add tags semi-automatically as each community could define relevant ones that'd trigger on keywords,.so a /c/Geology would have /t/Rocks suggested triggered by "rock" or "rocks" (where a /c/Music might pick up "rock" and offer /t/RockMusic). Someone posting would be offered the automatically generated tags to accept, remove or add others from a drop down menu. Posts without tags get flagged for moderators to look at.

Not sure if you'd allow users to create the multi-communities or leave it to the instances admins and/or mods or have a half-way house where users can create them and suggest them to admins.