In Fedora 16 (and I presume other distributions using gnome3), each print job generates a notification. If one prints a lot, this ends up cluttering the notification bar.
mkasik kindly pointed out how to make these notifications stop.
But this will also turn off “gsd-printer” which is used for installation of newly plugged printers.
At the time of writing this (2012-05-18) there is no finer grained control, so you have to choose which you prefer.