When my laptop resumes from suspend I see a notification that my wireless connection if gone and I am now offline. That is a rather unneeded message imho, because the state change happened during suspend and not during resume. This is not my problem though, just an annoyance. What _is_ the problem is this message is being displayed too long, because almost immediately after showing this message, my wireless reconnects. This state change is queued for notification, but the disconnect message is still showing. This means the message says my wireless is disconnected, but the status icons says its connected! This is clearly wrong! When a condition occurs that makes notifications in the queue or being shown obsolete, these notifications should be removed immediately.
I agree, notifications are displayed for far too long. It takes maybe 1-2 seconds to read a notification, yet notify-osd uses something like 5 seconds. This is especially a problem since they are queued up, so messages have to wait in the queue to be displayed, and by the time they get displayed they are no longer relevant.