I'm suggesting that when you click on the alerts tab and the drop down menu drops the number in the red box goes down to zero. I just read a PM and after i replied and kept browsing the forums i still had a alert for the PM as if i hadn't read the message. Kinda like how FaceBook is. My friend uses FB and when he clicks this little earth thingy the number on the amount of notifications he has drops to nothing and no number is shown.