You can kind of think of relays like subreddits, or an RSS feed, or an old-school web forum. Interest based, geo based, topic based, etc. In the future, there will be a nostr relay for everything. You’ll just add a new relay to your client when you find a new thing you want to join.
Can the information easily be copied to other relays in case the the big relay becomes a bad actor and starts censoring people
It’ll be up to your client to cross-post between relays. Maybe you run your own private relay that saves a copy of every post you’ve ever made so that if you get banned somewhere it’s all still available on your personal one.
Yeah, this is hypothetically what differentiates Nostr from mail servers. Switching mail providers has the high cost that you lose your identity and have to start over, and so mail providers have a lot of sway over users. As it stands relays have no sway over users or their identity. You can jump ship to another relay whenever you see fit, so that’s promising
And if you run your own private relay that your client cross-posts to, your follows and content comes with you.