i've got a very faint idea of an example feature being the "fridge" which you would stick the notes onto... hmmm. but i think you could share files too, it must have been like a curated web server.
it wasn't for file-sharing primarily, you could leave notes for people and stuff.
also i remember old Opera having a weird, interesting P2P thing built into it. one of the few features i never used
i said: building in an ad-blocker might be less flexible (re: upgrades etc.) than just doing it as an extension. remember the doomed "Flock" that tried to 'build in' all the social stuff? it bombed.
yeah, the VPN and built-in adblock were why my friend was asking about it.
Edge happens to be my main browser right now, but I might install Opera again in the near future to test the built-in VPN.