Comment 7 for bug 334809

I think the main problem here isn't about other bubbles waiting time. It's all about user interaction. Everyone expects his computer to be smart, while it'll be stupid to show a notification after 5 minutes it was sent. A notification is something important now, not later.

Moreover if the top-right corner of the screen is blighting every 7 second for 3 minutes a user won't look there anymore until the congestion ends. So all notifications in that stream will be useless.
It's my opinion that a notification system should have some kind of Quality of Service guarantee from the user point of view.

It's possible to silently drop long waiting messages? In this way we can detect any abuse of the notification system and restore a normal situation.
Let's consider a timeout of 90 second, so it's possible to deliver almost 13 notification in that time. Even a more aggressive value can do the job.