
MPT has posted an overview of the conceptual framework for “attention management†at https://wiki.ubuntu.com/NotificationDesignGuidelines, which puts ephemeral notification into context as just one of several distinct tools that applications can use when they don’t have the focus but need to make users aware of something. That’s a draft, and when it’s at 1.0 we’ll move it to a new site which will host design patterns on Canonical.com.
There is also a detailed specification for our implementation of the notification display agent, notify-osd, which can be found at https://wiki.ubuntu.com/NotifyOSD and which defines not only the expected behaviour of notify-osd but also all of the consequential updates we need to make across the packages in main an universe to ensure that those applications use notification and other techniques consistently.
There are at least 35 apps that need tweaking, and there may well be others! If you find an app that isn’t using notifications elegantly, please add it to the notification design guidelines page, and if you file a bug on the package, please tag it “notifications†so we can track these issues in a single consistent way.

Source : Mark Shuttleworth Blog Archive New notification work lands in Jaunty