[wheats]

This is also true of Mastodon. If you join an instance and change your mind you can switch instances and take all your follows/followers/posts etc. with you.

In both situations it is a major interruption to the sign up process and forces you to confront what you want out of the platform before using your account though -- I just wonder if there's anyway around that, Reddit seems to have decided there isn't one.

[Tomte]

As far as I understand it (and I may be wrong) this depends on the old server playing fair (and still existing).

It's not like email or a web site where you change your DNS records without any cooperation from the old server.