Nobody knows. It's a mystery.

You can think of nostr as passing notes in class. Relays are the desks in between who "pass it on".

Every time I post a note or comment or anything on nostr, that gets sent to the relays I'm connected to. Those relays then serve up my note to everyone else that's also connected to that relay.

nostr:note18pdj7lteu4vd58s8ecl54sxd8suqzhqxkyjztflt50jl099eh90s6vdwks

🫂

https://nostr.how/en/relays

https://voltage.cloud/blog/nostr/the-essential-guide-to-nostr-relays/

It's just a server that you connect to. Check my notes. I have a banger explanation from earlier today.