neighbourhoods
https://neighbourhoods.network/
good presentation: https://www.youtube.com/watch?v=OlnjJq3vOOk
a modular, open-source social media set of social media protocols being built on top of holochain. you can build your own applications using/sharing different layers of data/information with different groups based on that. i've been watching its development development from far away since late 2022, and like holochain, it doesn't seem to move fast... still, quite powerful if actualized.