Samsung to Use Earth’s Magnetic Field for Device Locating
...the app maps the geomagnetic fields distorted by indoor magnetic objects. By charting the pattern of the Earth's magnetic field as it warps around household gadgets, such as TVs or fridges, the app can tell the difference between a person's desk at home and a desk at work.
The idea is not to determine address type location but rather, more detailed indoor locations, so that a device can launch different app depending on its position in the house or office. So, put a Galaxy Tablet near the TV/Tivo, it will download shows; put it on the desktop and it will launch e-mail, etc. You have to set up the zone and what happens where, but staffers who saw it at Mobile World Congress said it did the job well. The app is expected by year end.