Interestingly, Sony is calling it a mock-up, but we assume that not too much will change for it and the Eye before the PS4 launches. Now we just need to know what the actual console will look like...
As we said, Sony was quick to point out to GDC-goers that this is a mock up of the controller. Could the overall design actually change? It could, but given the fact that it's now been shown off at both the PS4 launch and now, GDC, we assume Sony are confident that the controller that ships will look pretty much identical to this.
This is where the PS4 controller communicates with the new look Sony Eye, working pretty much as the current Move controller does. This means the PS4 can accurately track things, such as the height at which you're holding the controller, the distance you are from the TV and more.
Much was made at Sony's PS4 launch of the share function — the ability to have friends see what you're playing, upload clips of what you've been doing, even have friends jump in and take control of your game for a small time. The dedicated share button is the "instant on" for many of these functions.