Posit: there hasn’t been a sustained break out social app not funded by a big tech company since Snap?

Roblox, Minecraft, Fortnite and others are big hangout places for many teens and kids.
They're not "social apps" but a lot of socializing happens on those platforms. Probably also on Fortnite, FFXIV and others.

The open web is dead, long live the open web. ⌐◨-◨

Building /warpcast and /farcaster

— gabrielayuso.com

I would definitely consider these social apps, at least in how kids use them, even if they weren't designed to be "social networks"

My kids always check who's online in Roblox