1. Nostr is protocol so there can be multiple browser or native (android / iphone) clients. Website you use is just one option to use nostr. With your private key you can take your profile+data and "import" it to another app/website.

2. Nostr is open-source and free to use gor anyone so there is no owner. Even you can start building nostr, no need for ask permissions.

3. There is two essential components on nostr. Clients (website or your native client) and relays (dum servers relaying messages a.k.a notes to clients). You can connect to any free relays, so if one relay owner think, they should ban/censore you, others are still relaying your notes. You can easily run you own relay too and be sure your data is never lost.

4. Cyborg aint moderator, but i think that was joke, not sure. 😄🤷‍♂️