I've witnessed Apple's version of notifications, on both the iPhone (since dumped for a Droid X) and iPad. Please, let Growl's ownership remain exactly where it is-- or anywhere other than in Apple's hands!
Growl is quite horrid, and it seems to sneak into my system now and then bundled with apps.
Edit: Just checked it is even installed now... Again.
I hate Growl. I hope Apple never implements anything similar to OS X.
I agree ... Growl is a sneaky app that I have no use for.