The #threadiverse growth, so far, is exhibiting some nice instance parity.
See: https://fedidb.org/software/lemmy
Top three #lemmy instances (lemmy.ml, lemmy.world, beehaw.org) are all basically the same size.
With #kbin 's kbin.social and fedia.io (run by infosec.exchange) in the same range.
I experienced it today looking for #NBA communities for the #nbaplayoffs , and it seems the biggest community right now (after literally 1day) is on lemmy.world not lemmy.ml
Otherwise, probably one of if not the biggest experiments being run on the #threadiverse right now is how groups/communities run when decentralised at substantial scale.
Spread over instances will create more duplication/parallel communities than on Reddit, but will this be a good thing for diversity, or, a turn off with similar engagement issues some twitter migrants found here.
ATM, my feeling is, provided the UX is good enough, that it will be a pleasant balance.