1. Nostr is a simple, open protocol for decentralized, censorship-resistant social media.

2. It is not an app itself, but a foundation on which developers build applications.

3. Users create accounts with cryptographic key pairs, ensuring a self-sovereign form of login.

4. To interact on Nostr, users run a client (app) and connect to relays (servers) that pass messages between users.

5. Nostr clients are interoperable, allowing seamless communication across different platforms.