Innovation is king in the smartphone industry. Anyone who wants to stay on top has to continuously shake things up. The iPhone 3GS was a big success, but if Apple wants to beat RIM they're going to need to bring more to the table. One of the big criticisms a lot of folks have with the iPhone is that its screen does not offer any tactile feedback. There's a patent application out for an iPhone screen that features haptic feedback technology.

This haptic screen consists of a bunch of piezoelectronic actuators that all emit different frequencies, which lets the developers program them to mimic the feel of different surfaces. Supposedly, this would let Apple simulate a trackball on the screen that feels so real you can find it without looking.