[panglott]

"Scuttlebutt is slang for gossip, particularly among sailors. It is also the name of a peer-to-peer system ideal for social graphs, identity and messaging. ...Secure Scuttlebutt is also different to federated social networks like Mastodon, Diaspora, GNU social, OStatus. Those technologies are not peer-to-peer, because each component is either a server or a client, but not both." https://staltz.com/an-off-grid-social-network.html

It's also a system with a clear, although niche, use case that adds value in a way that FB wouldn't.