Apple added something new to the iPad from the moment of it’s unveiling. Unfortunately, this is not a front-facing camera as we all hoped; this is new button locking the screen orientation.
That means that you can lie sidelong holding your tablet in any clumsy position you like – however, as Jony Ive says, there is no correct position to hold iPad – and the screen won’t skip back and forth between portrait and landscape orientation. I personally hope Apple adds this button to the next model of iPhone also.