The technology in the linked article would appear, at least superficially, to be similar to RFID. Although one difference might be that RFID works at a fixed frequency (to match the harmonic frequency of the receiving radio circuit) whereas this apparently works with "ambient" radio, implying a broad spectrum of frequencies, which is quite clever.

Either way, the broadcast signal is losing power at a rate proportional 1/d^2. So these devices necessarily have to work at very low power. What Tesla did - or is supposed to have done - was to figure out how to transmit power without the 1/d^2 loss. I.e, much like a collimated laser beam, he could transmit power over large distances and power high current devices.

He had dramatic ideas for free, wireless power transmission for everyone. His wealthy backer (was it JP Morgan?) said he couldn't see the profit angle in that and wasn't interested, saying something like "Where do you attach the meter?".

Not exact quotes, but the source is my print version of : http://books.google.com/books?id=40NzjS5FunkC&printsec=f...;

This is same technology as crystal radio of first half of 20th century, which was also powered only by absorbed EM energy (which is also same as passive RFID and similar things). Tesla's designs are slightly different (in that they are probably not exactly wireless). See http://amasci.com/tesla/tmistk.html