I forked the topic, it deserves a longer reply and isn't as related to the earlier topic.

@reynir@forum.fedi.dk that's a very good question, and having experienced it firsthand, I will share what happened.

I started a climbing news aggregator based off of NodeBB at https://news.crag.social, and enabled federation. Later on, the forum rebranded under the OpenBeta umbrella and the domain name changed to community.openbeta.io.

This was the best case scenario, a NodeBB to NodeBB move. Every user maintained their accounts, maintained their public keys, and the only thing that changed was their id. I set up a blind 301 redirect to the new site, so every single URL (whose structure was unchanged, remember) went to the new URL.

Everybody still lost all their followers. The problem wasn't on my end, it was that remote users are tied to their ID and even though I left a redirect on the old domain to the new one, the support for this in other software is basically zero.

There are efforts to look into this, re: Account Portability, but I am unsure of the status of this work.