Thanks. I am more worried about the identity than the posts. If my identity belongs to the host, then in that sense this is no better than a centralized Twitter. Just theoretically speaking (I have not been banned from anything ever), if a mastodon.art user is banned from mastodon.art - everyone who followed them will have to find them on another instance and subscribe again? If exporting data is a process that depends on the host instance, when they ban you - that's it, your identity is not recoverable.
The migration tool automatically moves your followers. It's a bit janky, it took an hour or two for it do its thing for me (there must be some batch component, I dunno). I don't know how it works between banned instances, or what your options are for when a server goes down fully.
But all the of the follower/following data is available via CSV export any time, too. And there's obviously an open API as well.
And honestly, you could also just run your own server if you're that concerned.
How are permissions managed so that you can change your followers configuration to point at your new account if you move, but otherwise not allow anybody else to pull that same stunt against your wishes?
IMO the bigger issue isn't getting banned, it seems the more likely scenario is having the operator of the server decide for whatever reason to shut it down. This isn't likely to happen with Twitter.
It's perhaps less likely for Twitter than any one given Fediverse server/Mastodon instance. But the impact on the whole ecosystem is very different too. A single Fediverse instance shutting down could be annoying/sad, but it would only affect a subset of users, and those users could still, if need be, create a new account on another instance. Twitter shutting down closes everything for everyone.
Relatedly, Twitter isn't going to throw a bake sale to try to stop from shutting down, it will get devoured as quickly as it files Chapter 7 or Chapter 11 and debt holders descend like vultures.
Most Mastodon instances are community run, and when they hit some rough straits in paying for their hosting some of them will have a (metaphorical) bake sale encouraging users to contribute to the hosting fund Patreon or will ask around if someone wants to take over the admin hot seat for a while.
For those concerned about the longevity of specific instances that's generally the answer: ask the community how the admin pays for things, look for their Patreon, consider chipping in what you can each month.
I agree. The idealist in me wants all of these aspects to be completely independent from the host I choose to use. But realistically I am not that worried about losing data, the social graph is far more valuable. Even if I have 100 followers, I would still really want to preserve their connection to me if I am banned.
I understand that I can do this by hosting my own instance - that's a good enough solution (for me).