It doesn’t matter which one you sign up for. Most of them talk to one another. For example. Lemmy.ml people can subscribe to and read Lemmy.world communities.
Lemmy can also talk to other “fediverse” social media platforms like Kbin. You often see a lot of Kbin users in Lemmy comments.
Basically there are many different Lemmy servers. Http://lemmy.world Http://lemmy.ml Http://shit.just.works Etc etc
It doesn’t matter which one you sign up for. Most of them talk to one another. For example. Lemmy.ml people can subscribe to and read Lemmy.world communities.
Lemmy can also talk to other “fediverse” social media platforms like Kbin. You often see a lot of Kbin users in Lemmy comments.