When @ at someone, it would be good to know when he/she types an answer. Just like in popular IMs like Facebook, Gmail etc.
I disagree, basically because we aren't an IM client - we're a chat room. I think all that would do is just add more data for the servers to transmit, and doesn't really benefit us as a whole in the end.
Also it's slightly creepy I find.. Much easier to just wait for that sound you hear when someone @'s you back.
It's also a bit ineffective when you have 20+ people in the room.