The Associated Press reported in April 2009 that James Harrison of Graham, Washington, tracked his wife by using her cell phone's GPS feature after he suspected her of infidelity. He found her with another man and, in a rage, killed his five children and himself later that night.
Smartphone Maps and Apps
Aside from friend-location software for smartphones, map-based apps can divulge considerably more information than just where you had lunch. Sites like Foursquare, a game in which you log your location to gain rewards from bars, restaurants, and shops that you visit, and Postabon, where you post shopping deals as you see them, have corresponding apps for posting updates on-the-go from your smartphone.
When you post to these sites, a geotagged map specifies the location of the place you are referencing. A person could easily find you through Foursquare, check which places you've logged into, and spot a link to your Facebook and Twitter presences, depending on what your security settings are.
If you use the new Google Buzz service on your smartphone, you've probably seen the map that pops up after you buzz. There you are--a bubble-marked dot on a map, surrounded by other dots linked to what other users have buzzed about in your immediate vicinity. So you can see, for instance, that John Doe was at the pizza place across the street, and that Jane Smith was meeting a friend right around the corner. And because Google encourages users to provide their first and last name to boost their public index, a particular person's footprints are even more noticeable.
Though it offers a legitimate (and cool) way to organize photos and posts, geotagging is also a stalker's dream function. When you geotag a Tweet, a review, a post, or a photo, metadata logs the exact time when that piece of data was captured and the exact geographical location where it was captured.
A follower with serious boundary issues might plug that information into Google Maps to get a street-view location, so be careful with the data you include with photos that you plan to share online.