We have Lemmy.world, Lemmy.ml, beehaw.org, I think even yiffit.net. If I log in using wefwef it asks me where I want to login. And when I make a new account using another instance, it says ”… Lemmy is federated, so you can interact with everything on lemmy.ml even if you’re registered on a different instance.“ So if I’m registered on lemmy.world, how can I interact with lemmy.ml?
Yes you can! For example, click this: !memes@lemmy.ml
That’s a lemmy.ml community. But you can post there, comment, vote, etc. You’ll see posts and comments from users on different instances all the time. Sometimes you’ll see different platform users like Kbin and Mastodon users posting and commenting!