User accounts are fragmented and just because you signed on at lemmy.world doesn’t mean your account exists on lemmy.ca.
https://github.com/LemmyNet/lemmy/issues/1985
Communities are fragmented and /c/games on lemmy.world is completely different than the one on lemmy.ml with its own users, set of posts, etc.
Lemmy does not currently allow for instance or user migration.
https://github.com/LemmyNet/lemmy/issues/3057
Nor does it allow for shared communities (ie the aforementioned /c/games is unified across multiple instances)
https://github.com/LemmyNet/lemmy/issues/3100
We are in the early days. If you’re eager feel free to join in the development on these any many other core issues. There’s real potential here.
I could see this becoming a massive issue when the Fediverse becomes popular enough for niche internet microcelebrities. People like u/SirLulzingtonEsquire, who invented a whole new genre of trollface comics on Reddit, could get impersonated on a platform like this. It also seems like it could be an issue for actual celebrities. Remember what happened when Elon started selling blue checkmarks?
I’d like to hope that by the point this could become a major issue, there would already be a proper solution proposed. Probably the easiest way would be to include your full username + instance name on a public facing website, though obviously not everyone has one.