For example, General Electric has developed the a home energy management platform that uses a ZigBee network protocols to establish communication channels between household appliances.

FORBES: University Launches World's Largest CO2 Emissions Tracking Portal

As Technology Review's Physics arXiv blog reports, they've devised a means to modify a standard 802.15.4 wireless network (commonly used by home automation services like ZigBee) to actually "see" movement through walls, and with some degree of accuracy, no less.

ENGADGET: Researchers create Amazing X-Ray Wireless Network!