@atomicpoet If you mean being able to move a public identity between implementations, that's what the URL- or Webfinger-based identity is supposed to let you do.
You should be able to export data from a Mastodon server, import it to another system, change the DNS, and everything just keeps on working.
I realise that's not how things work right now, but that's the intention of the protocol. Your identity is your Webfinger, and you can move it where you want.
@evan I guess one of the frustrating aspects of ActivityPub is that it can do a lot of things “in theory”. But so much of its potential isn’t being fully utilized in practice.