With reddit we mostly had a single subreddit for a given topic, for the sake of the question let’s use gaming. If there were alternative subreddits dedicated to the same topic, they had names that gave that away. Do you think Lemmy will lead to more segmentation, and more information bubbles seeing as we now can have gaming@x and gaming@y without a obvious way to see which community is the “default” one? Will it be a good thing, as you can find a community that suits your preferences better, or will it stifle discussion?
I think people are worrying about it too much.
On Reddit, there were tons of duplicates. r/tumblr and r/CuratedTumblr. r/animemes and r/animememes and r/goodanimemes. r/gaming and r/games.
For Magic the Gathering there was r/magicTCG, r/mtg, r/magicthecirclejerking, r/MagicArena, r/EDH, r/mtgmemes, r/mtgfinance, r/ModernMagic, r/Pauper, r/mtgbrawl, r/DinosaursMTG, a bunch more, plus probably a dozen more I didn’t even know about.
Dungeons & Dragons had r/DnD, r/dndnext, r/onednd, r/DungeonsandDragons, r/DnDMemes, r/3d6, and again, lots more.
If there are enough people in each community, great! More communities! If not, that’s still okay! People will naturally gravitate towards more active communities. A lot of the duplicate communities will eventually figure themselves out and one will become the “main community.” We just have to wait a bit. For now I’m just subscribing to anything that matches my interest to see what happens with it.