This is a critical feature missing. Especially considering when one instance goes down, so does your account.
If announced, we should be able to easily transfer the account.
But an instance might also go down unannounced (especially now with so many hosting instances just for fun or to experiment with it).
While in such a case your posts and comments on this local instance will be gone, there needs to be a way to recover your account on another instance with all your posts and comments made on other instances still connected to your account, being editable or deletable.
There isn't much left.
First Facebook with their whole meta thing, then Imgur deleting all NSFW content and images uploaded by non-registered members, afterwards Twitter and now Reddit.
Twitch made a big mistake with their new sponsoring rules, but seems like they are reverting / changing it again due to bad community feedback.
Discord had a few changes the community didn't like, but nothing ground breaking yet. But they get more and more greedy and their platform is filled with scams, hackers, bots and sadly many bad people like child predators and content which Discord support does nothing against. They seem not to care.
YouTube, well, I think they might be next actually. More and longer unskipable ads, restricting or demonetizing many videos, bad communication with their creators and less rewards for smaller creators. In addition, they might put high quality resolutions behind their already existing expensive subscription paywall. There isn't any competition which is urgently needed.
UPDATE: Bad news about YouTube continues. Just now, YouTube Ordered ‘Invidious’ Privacy Software to Shut Down in 7 Days.
Which other big social media platforms are left?
@Nankeru
@feddit.de