There are many reasons to enable [1] Find My iPhone, but a 28-year-old Campbell, CA, resident discovered one of the more harrowing ones: being stuck in a ravine. The San Jose Mercury News reported that one woman was trapped in her car and found by police using Find My iPhone [2].

Apple's iCloud service located a 28-year-old woman who spent 18 hours at the bottom of a 500-foot ravine. Tuesday morning, she was rescued via helicopter and flown to a hospital. One tech-savvy police officer used the Find My iPhone app on an iPad to view the location of her iPhone.

It's easy to sign up for Find My iPhone. Simply log in to iCloud or download the Find My iPhone [3] app on an iPad or iPod Touch to view the phone's location, lock or wipe it remotely if it's been stolen, or put it in "lost mode," which tracks the device's current location as well as location history. Apple has a database of WiFi hotspots and cellphone towers around the country. It uses the nearest cell towers as well as hotspot locations and GPS to determine the iPhone's exact positioning. Since it's free, you have nothing to lose by signing up!