A gossip peer-to-peer protocol.
Feeds are represented as a hashchain of signed messages.
A truly peer-to-peer, uncensorable and offline first messaging app.
Based on IPFS
A radical no-metadata messaging app. Every message is a hidden blob that you will try to decipher with all your keys, if you succeed, the message is for you. (Scaling is a issue)
TOR-routing of messages is also offered.
A social network on a blockchain (Polygon).
Personnal consideration : I don't know if a pure on-chain approch could scale well, every validator would have to validate every post, comments, likes, ...
See : lenster.xyz, mirror.xyzhttps://blog.ceramic.network/tiles-a-browser-for-open-source-information/
https://twitter.com/LuozhuZhang/status/1530984087061929984?s=20&t=_6d66haeswHBHNn4cEB46A
https://research.protocol.ai/sites/snarks/