I've been doing a security presentation at work about phones with GPS and camera capabilities providing means to stalk the unsuspecting user. A lot of people here were totally unaware their phone is providing this info, so I thought I would pass it along.
In a nutshell, iPhones, Androids and Blackberries among others record the GPS coordinates of the phone (called "geotags) when the picture is snapped. This info is saved in the metadata of the photo.
If you upload the photo to many webservices, including facebook, twitter, Flickr, etc., the metadata goes with it, so, by extracting the metadata and putting the coordinates into a map service, you can get an exact location of where the picture was taken.
Some people and websites see this as a feature. Unfortunately, it can also be a stalker's favorite tool. Imagine a cute picture of your 9-year-old daughter in the living room, excitedly holding a Justin Bieber calendar. Her name is on a certificate on the wall behind her. You post it on Flickr. "Mary's just crazy about Justin."
Creep drives to Fairhope, AL. "Hey, little Mary, want to see a cool picture of Justin Bieber?" The metadata tells the unscrupulous when you shot the picture, how to get directions to the house, and, to boot, he can see a flat panel TV and computer in the background, just in case burglary and not child abduction is his thing.
Yeah, it's a bit paranoid, but just another bit of personal data you should know about so you can manage it. Features like this are usually defaulted to on, and only a few web services prompt you to not include metadata.
Here's some links:
http://redtape.msnbc.com/2010/12/ten-things-web-users-should -fear-in-2011.html
http://icanstalku.com http://www.nytimes.com/2010/08/12/technology/personaltech/12 basics.html?_r=4
Our company issues iPhones to certain personnel. So far all but one were defaulted on for the coordinates to be included in the metadata.