Nah, I don't know about you guys but receiving a PM, reading the pm, clicking the post where you're tagged and viewing it is so much effort. Tagging is for special occasions or direct questions or you want them to read something.
There's lots of quotes on here that result in replies with "Liked", "Repped", "This." etc. However, a small notification which doesn't involve having to open a PM when quoted would be nice, that's what the notification system would be like. So much more user-friendly.