Geolocation services such as Facebook Places, Foursquare, and Gowalla let you tell the world what you're doing and where you're doing it, but they're voluntary. Other people may be tracking you in secret, thanks to that homing beacon in your pocket.

In September, a federal appeals court in Philadelphia ruled that before obtaining location data, though a judge may still request one. (Conversely, last August the U.S. Court of Appeals for the District of Columbia ruled that on your car.) Until the Supreme Court issues a ruling or Congress enacts laws making location privacy a priority, the rules will vary depending on your location (appropriately enough). Meanwhile, private businesses can use your location data as they wish.

The solution: Turn off all of your handset's wireless antennas when you feel the urge to roam free.

Threat Level: GREEN