Multiple displays is an theme throughout all at-home consumer electronics. We need a technology that can be streamed to as an external display instantly anywhere that can be any size.
There are several competing standards. "Wireless HDMI" is a gaggle of unlicensed spectrum, but they manage to get 1ms delay with propriatary techs. We've had WiDi (with varying lag) and miracast (with awful lag) for a while, but nobody's been able to manage to standardize the standard, so to speak.