We've seen the United States Patent and Trademark Office reject or invalidate a few important Apple patents in the last few months, including one covering the infamous 'rubber banding' UI feature, and one covering the iPhone.
Today, the USPTO added another key patent to the list, tentatively declaring Apple's US 7,844,915 invention — widely referred to as the pinch-to-zoom patent — invalid. It's just a preliminary decision, but it's still a fairly big deal...