I've only ever been linked to a few of the /v/ the musical tracks on yt for one reason or another, but it's as good a way as any to find new music I suppose.
When I was younger I'd heard new music from the radio just because it was always on, then MTV, then downloading random/related stuff on napster or forums. I still hear new stuff I seek out from yt and films but I mostly go looking for it. I have slowed down in the last few years though, just don't have as much time.
I don't think people still scrobble but; last.fm/user/butterdog