The_AV8R writes "Jonathan Zdziarski showed that every time you press the Home button on your iPhone, a screen capture is taken in order to produce a visual effect. This image is then cached and later deleted. Zdziarski says that there have been cases of law enforcement looking up sex offenders' old data and checking recovered screenshots." This revelation occurred in the midst of a webcast on iPhone forensics, demonstrating how to bypass the iPhone's password security (not trivial, but doable). Video from the talk is not online yet but is promised soon over at O'Reilly.