Nostr came out in 2020 as a decentralised protocol for social networking and publishing. In nostr, there are no servers. There are only clients and relays: clients post messages, relays transfer them to other clients.

Identity in nostr is based on public-key cryptography: your public key is your identity (like in Bitcoin) and your private key is your password. This means that identities are not tied to particular servers, domain names, or anything else. They are just two keys that sign messages.

This is interesting because it's radically simple, it's just identities and relays. How far can you go with such a simple protocol?