Nostr is like Twitter, but instead of an algorithm deciding what you see, it's more like everyone yelling at each other in a giant digital stadium, and you get to pick which yellers you listen to. Instead of centralized speakers, there are "relays," which are like constantly running bulletin boards that anyone can post on, kind of like digital graffiti walls, but with more crypto bros and less, uh, artistic expression. So, yeah, Nostr. It's... something.