Non-focus-stealing off-center dialogs:
A failure message occurs in a non-modal window that opens in an unobtrusive location, and goes away by itself after a time-out. In my prototype implementation, the dialog is canary in color, about 1/8" down from the top of the screen, just to the right of center, and fades out after about 5 seconds much like the new MicrosoftOutlook message notification window.
There's still an unresolved issue about what happens when user actions in progress generate several failures in sequence before the first message can be seen.
See also: SilentFailureNoisySuccess