[mumblemumble]

There's this sort of thing, definitely, but I'll note that Facebook lacks many of these features, and is still a toxic environment, although perhaps less overtly so.

My own guess is that the most fundamental problem is that Dunbar's number is real, and bad things happen if you blow past it. Large scale human communication works best when it is not modeled as an endless, 24/7 masquerade ball where the theme of the party is bullhorns.