My idea is; Whenever you get a PM, your computer makes a sound to alert you of it. I hate it when I get a PM, dont notice it, and it goes unchecked for a few days. Some people get quite a bit of these, so I also suggest a feature that lets you turn it off.

You can already set it so that you get a pop-up alert when you get a new PM, and you also already have the ability to turn PMs off.

oops, my bad. XD