Nostr isn’t itself a social network. Instead, it is an open protocol with a lean toward censorship resistance. The protocol doesn’t use a centralized server, instead relying on user-run clients. With this client, users can send content around by writing a post, signing it with their private key and relaying it to others’ servers. This relay network can enable others to build social media platforms using it.
Source: https://www.coindesk.com/business/2022/12/18/warrens-reactionary-crypto-policy-vs-dorseys-decentralized-social-media-gambit/?utm_medium=referral&utm_source=rss&utm_campaign=headlines