Thank you Gurjyot. This is one more feature I would like- getting a notification for @arjunsuresh- which basically means a user allows himself to be tagged. So, this must be a user allowed option. Now, there should be a editor plugin which allows autofill of usernames as we start @yyy first three letter of names. I guess the difficulty here is it needs 2 parts- one for editor and one for Q2A.