Not !fs as far as I remember (actually, I remember reading about how there were multiple variants being used, with varying popularity).

I explicitly remember reading about how it was troublesome that iOS users couldn't communicate with Android networks, as the most common p2p method was some kind of bluetooth meshing-or-comparable-technology. And Apple only allows audio streaming over Bluetooth, making it utterly useless in a scenario like that.

I think the meshing was made possible by hacking the MAC broadcasting, embedding a data layer in the discovery mechanism.

And maybe wifi hotspots were used, but then even Android 802.11 mesh capabilities are not available (or were at the time at least).