The data this is based on comes from https://lemmyverse.net where you can just download a full json of the data they have (I excluded all communities marked as "suspicious")
EDIT: The data if you sort by active users last month:
Duplicate instances are a problem imho. You can see the network effect synergy working by how many communities flock to the biggest instance lemmy.world.
There also need to be tools to merge two communities on separate instances, or move them.
Two of my niche instances tried to leave reddit, but then there were two versions, one on .ml and one on .world. Confusing. Maybe there need to be reviews for communities or instances.
I wouldn't mind so much if there were a way to see duplicate posts across instances. I guess it'd be hard to implement but as it stands unless it's specifically a crosspost you can't find other discussions of the same media
Oh yeah absolutely, lemmy definitely needs better cross posting. Currently crossposts are kinda yanky with quote blocks. I'd also love to see reposts that are detected automatically.
There also need to be tools to merge two communities on separate instances, or move them.
The issue is not the tools, more the people. I contacted mods of !android@lemmy.world and !askandroid@lemdro.id a while ago to see if they wanted to merge, both sides wanted to stay on their own communities.
There are plenty of other examples, usually a large LW community, but with a more active non-LW alternative. LW wants to keep their community open, and the non-LW doesn't have much power besides showing they are more active.