I think you got it, but it's a bit simpler than "Nostr code".

Just like the internet works with HTTP, you send out data in the format defined by the HTTP protocol and your router and lots of other computers around the world all know how to read, transmit and/or present the data.

Well nostr notes are a bit like that, it's data in a structured templated format. As long as the data is in a nostr form, it is basically free data and has the following properties:

1. You said it, but yeah it's signed using a personal secret key.

2. It is just data and can live anywhere.. You can back it up on your laptop. Because it is self contained data and signed, you don't need to have the data served by Elon's servers to know who sent it.

You publish it on many "relays" which is like a http web server but instead of it hosting YOUR webpages, it can be given notes and it can relay or serve those notes on your behalf. Again, it doesn't matter who serves the content.

So if one relay disappears, the others have it. Also if you back it up yourself, if the data goes missing, just republish it.

Yes a relay can still delete your content. But now it's on many servers and you don't put your trust in any of them to protect your reputation because your signature does that. So what's the realistic chance that all relays that you posted to decide to delete your posts when they aren't all in a single country or jurisdiction?

The big "problem" is discovery. Now that content you are interested in can be practically anywhere, how do you find it? Fortunately wherever it is, your favourite client can read from it if you tell it about the relay. Think: Darknet Tor web addresses for those who know.

Best still, take one relay down, guess what happens... Hydra.

So the big if IMO is whether people will stick to just a few big relays that are "safe" and regulated or if it just becomes normal for content to be all over the place and the clients just find it.