If you look at the links by each post, you'll notice that some will reference a URL that goes off of your local instance. In Lemmy these are icons, in kbin it appears from the "more" link. Sometimes it's unclear who/where I'm interacting with and examining the URL helps me get some idea of it. In federated social media different instances often develop a different subculture, but since they can access each other you have more dimensions of interaction and how to behave.