Psuedotransparancy for occlusion-free direct input.
Sounds like a lot of big words, but what it actually means, is: this is really cool! Watch the video to get a full understanding of the potential of this technology. When the tech catches up with the concept, I see this as being a big handheld revolution, whether it be game console, phone, pda or all of the above..
"A touch-sensitive gadget with the sensing panel on its back, instead of the screen, is being developed by US researchers. Using your fingers behind the device allows a firmer grip and more accurate performance without obscuring your view of the screen."
Source: NewScientistTech