On command line tools it'd be useful, but also on other places, for ex a screensaver displaying random pics form the disk... if it opens a file that requires displaying an alert it would both look bad and be a security risk.
Definitely needed if we want to use them in a web browserProgressive rendering of an incompletely downloaded file would be nice too in this context.
-- Adrien Destugues / PulkoMandy http://pulkomandy.ath.cx
