@evan Bringing my own domain to somebody else who runs a multi-tenant server would be very nice indeed. I can bring my own domain to most e-mail providers and they will run e-mail for me at my domain, we should have the same here.
I want to do one better, though, which is mostly orthogonal to this: I want to go to lemmy.world and log in with @j12t and post, on that lemmy server, while being identified by that Mastodon-hosted identifier. Otherwise nobody knows it's me!