As seen in The New York Times on December 2, 2008:

Venturing Beyond a Compass and Map

By Ian Austen 

SPOT Satellite Messenger

Unlike conventional GPS devices, the Spot Satellite Messenger (also known as Personal Tracker; $170, findmespot.com) does not give directions. Instead, it tracks its user’s location and sends family and friends automated text or e-mail updates. If necessary, the device can alert up to 10 people that a user needs nonemergency assistance; another feature acts as a global 911 service for true emergencies. The Spot requires an annual subscription of $100 to $158, depending on services.