Using just light bulbs, to transfer data wirelessly

Watch the video below to see how Harald Haas explains his idea at TEDtalks, about a new method of transmiting data through our light bulbs.
The concept is quite clear. The light intensity changes at speeds the human eye cannot conceive, so without altering the lightbulb's primary usage i.e. illumination, a special receiver, can see those changes and translate it them into data.

The demonstration is quite impressive since he streams a video through a desktop light, and when he casts a shadow to the receiver, the video just "lags"