We are just now tapping on the spatial dimension of wireless channels; up to now we have just used frequency, time, and polarization for orthogonality. Spatial processing allows theoretically unlimited (bounded by computation, solved by Moore) channel capacity. At the same time, we are beginning to use the available channel resources more efficiently with cognitive radios, which allows much better spectrum utilization. Today, with statically allocated spectrum use, I'd guess that less than 10% of allocated spectrum and time is in active use at any time.