Passive Wi-Fi consumes 1/10,000th the power of conventional wireless networks.
A team of computer scientists and electrical engineers from the University of Washington has developed an extremely power-efficient version of Wi-Fi wireless networking technology that consumes 10,000 times less power than the current Wi-Fi components, allowing Wi-Fi networking to be built into a much wider range of devices. The team will present a paper (PDF) with the results of their research into what they have dubbed Passive Wi-Fi at the upcoming USENIX Symposium on Networked Systems Design and Implementation in March.
Read more at Ars Technica