Basically, this should notify you of various things of your interest, for example notifying you if your username has been changed, that you have been banned, promoted to a new rank, and other stuff like that. This may also be a way to get a private message system going; it may be able to keep track of private messages you receive.
This should appear as link in the toolbar that currently greets you with 'Hello ____'. A little emoticon should appear next to this link when you receive a message or notification, attracting attention to it when needed. The toolbar could look like this.
Just a suggestion. Came to mind after reading Dr.Flame's suggestion here.