Relays have 2 tasks: 1. Storing notes 2. Allowing people to query them When you connect to a relay, it uses the WebSocket protocol to communicate (that is what the wss:// is). HTTP is like asking someone something and getting an answer, WebSockets are like real time chat. Which is better for real time applications. When you first make and sign a note, you send it to a set of relays. Each relay takes your note and stores it, and adds it to indexes, like: - all kind 1 notes - all notes by semisol etc. Now, you can ask for it! You ask the relay for, for example all kind 1 notes from who you follow, and it checks the indexes for those, and sends you the matching notes it found. This is how a relay works. But on top there can be many features, for example: - nostr.land charges a fee for writing - many people host relays with whitelists - aggr.nostr.land reads all notes from other relays, spam filters them and stores them - hist.nostr.land retains multiple versions of events like a follow list - relays like blastr or nostr.land broadcast your events to hundreds of relays