"Yes ladies and gentlemen, it's official... Ubuntu 9.04 has a
whole new notification system, almost the same as the one in the
Macintosh operating system. The new notification framework was
named "Notify-OSD" and it can handle both keyboard actions such as
volume and brightness, and application notifications. What does
this mean? Well... for example, when a buddy goes offline or
online, when you receive a chat/IRC message, when a torrent is
finished, when you change the volume or the brightness of your
monitor, when new software updates are available, when a network
connection has been established... a very nice and stylish (black,
at the moment) notification will be displayed for a few seconds in
the top right corner of the screen."