So there's that content-aware scaling feature in Photoshop CS4, which just judging from the still images would seem to make it the most significant advance in digital photo processing since, oh, the original Photoshop.
Well, that's nothing compared to this video demonstrating how the technology works, from SIGGRAPH '07:
That is just devilishly clever.
Then again, so's this. I loathe this feeling: that these things are so obvious in retrospect that I know I could have come up with them, or something just as cool, if only I were just a tiny bit more imaginative.