Im joining in on the reddit ditching thing, and was kinda worried at first that i wouldnt be able to like use it the way i did reddit as it feels like a whole new place, but after engaging with posts and people and actually being a part of lemmy rather than being lurk mode all the time i was pleasantly surprised with how easy it is to become a member of the community, theres a reasonable amount of subs (or whatever the other word for em is) that fit my interests, enough linux content and shitposting for my liking, and the overall random posts made by people equally fed up with Leddit. (also i admit i used reddit a little cus there was this post on the fedora sub showing how to fix a sound issue i been having after a recent update)
Regarding your last paragraph, I agree. I’m subscribed to gaming in lemmy.ml and beehaw so see the same content twice regularly. Duplicate communities raise other concerns for me though:
Which one is the defacto community to join? Using the Gaming community as an example, maybe one leans more to images and the other has more meaty discussion threads just by way of who has joined those communities - nothing to do with the rules. But if you subscribe to both, the majority of the content may be duplicate posts instead? It’s not clear from the community title alone.
Is the potential squandered as communities are potentially splintered? Maybe people just stick to one community without joining the other. It’ll take time for a certain community to establish itself as the main community with the highest quality posts, but due to the volume of users on the main instances maybe there won’t be a main community? Or maybe people won’t even be aware of multiple communities for the same topic as the names are different, e.g. football Vs soccer.
All this fragmentation will reduce the adoption for sure. No one wants to write to a sub filled with 5 people while another is filled with 5k people. We should adopt one new fresh instance and make it our main, and point people coming from reddit to this new instance.