I'm subscribed and relatively active in a few communities in the Stack Exchange network. It is a nice feature of the site that notifications (both "message" and "rep" ones) are collected from all the networks one is subscribed to, eliminating the need to have to visit each network separately to find out if you have any new notifications.
However, it would also be useful for me to be able to tell visually if these notifications are exclusively from other network sites than the one I'm currently visiting. For instance, if I visit TeX - LaTeX, and I only have notifications pending from Stack Overflow, I would like at a glance to know that while I have notifications waiting, none of them are actually relating to the current (i.e. TeX - LaTeX) site.
A case scenario would be if I generally get a lot of notifications from Stack Overflow and not from TeX - LaTeX, and I've just asked a question on TeX - LaTeX regarding my thesis, and I'm expecting an answer and check on TeX - LaTeX periodically. I would like to not have to check every time I see a notification (which is more likely to be from Stack Overflow and a distraction from the current task) and only catch my eye properly if the notification originates from within TeX - LaTeX.
Perhaps this could be done with a more faded-out version of the icons currently used?