On my brief read of the whole project, 'reticulum' is not a name for a social media protocol but is instead the name of a completely decentralized, encrypted, cryptographically addressable, un-surveillable networking stack that could (should?) replace TCP/IP altogether. It aims to be the plumbing that the Internet should have had from the get go.

Within the small reticulum ecosystem, there is a social media / chat protocol that is built on top it which is called LXMF (https://github.com/markqvist/lxmf).