Before you proudly go posting photos of your Ming vase online, you should be aware that computer-savvy burglars can likely use that photo to find out where you live. The same goes for photos or videos of your kids, yourself, or anything else that you don’t want strangers knowing how to locate. The practice of tracking people via their posted images is an example of “cybercasing”, and is possible because many digital cameras and smart phones, including the iPhone, automatically geotag their images by embedding the longitude and latitude at which they were taken. Even when uploaded to a website, the images still retain this information. By plugging the coordinates into a service like Google Street View, getting an address or an identifying landmark is entirely possible.

This disturbing fact was recently announced in a report published by the International Computer Science Institute (ICSI). Researchers Gerald Friedland and Robin Sommer wrote that they successfully obtained the home addresses of people who had posted photos in ads on Craigslist, despite those people having opted to keep their addresses hidden in their postings.

Creepier still, they were also able to obtain addresses where home videos of children had been shot, by searching under the tag “kids” on YouTube. They then proceeded to search for recent videos from those same users, that had been shot over 1,000 miles away. Within 15 minutes, they were able to determine that 13 of these video posters were likely still away on vacation, leaving their homes available for burglary.

While iPhones do geotag by default, it is possible to turn the feature off. The folks over at I Can Stalk U (they’re against stalking, not in favor of it) can show you how. For other phones and cameras, a Googling or a look through your user's manual should tell you what you need to know.