Oh! Not Fedi, strictly speaking, but there is "Circles" - (circu.li). It's s matrix thing and I've been following progress, but lost enthusiasm when i brought up gplus (old hat here as well) and they said "recursive circles were to hard for them to implement".
Then, what's three point I thought. That's where the power of Circles really comes into play.
Did you see that IMDb thing that guys doing with his #Mitra fork yet? He's gonna keep it a softfork too.