I've been hearing about Mastodon for a while and I'm willing to try it out. Last night I learned that you can't keep your identity should an instance be shut down, which I am not a fan of. I was thinking maybe someone could build something on top of git, where as you gpg sign all your commits (messages/replies) and you can refer to them across repos (instances) and your gpg key *is* your identity. The biggest hurdle is probably user experience around key management. Like Bitcoin.