We all love posting our favorite photos on Facebook or Twitter to share with family and friends. But could those pictures be worth a thousand words...to thieves?
What most people don't realize is: when you take a photo with your camera phone or GPS-enabled digital camera that photo is "geotagged" with GPS coordinates of where it was taken.
"And the location can be as accurate as plus minus one meter, depending on the reception of the GPS signal of the device you're using," says Gerald Friedland, of the International Computer Science Institute at Berkeley. He co-authored a study on the privacy implications of geotagging and found most people have no idea what they're posting.
Of course location information, on its own, may not be a problem. Until, that is, you post the geotagged photo on the Web. Now that GPS information is available to anyone who wants it. Which can be a problem, according to icanstalku.com co-founder Larry Pesce.
"For example, let's take a picture of your nice brand new 50 inch plasma TV at your house and you're now sharing the location of that TV and an hour later you're posting a photograph from a 7-11 and now we know that you're not home."
Larry started the geotagging awareness website after learning that he'd inadvertently given out location information on his baby daughter. The website trolls Twitter for geotagged photos and then sends a tweet to random users, basically telling them they know where they live.
"We have three different typical reactions to folks getting posted at icanstalku," says Pesce. "They range from, 'Oh wow, I didn't know that was possible, thanks for telling me' to, 'Oh my, that's really scary, I'm going to find you and punch you.' And yes, 'You're not very smart 'cause I actually told you where I was.'"
One of their "victims" was Cristina Parker, who would take photos of her dog and post them on Twitter. Until she got a tweet from icanstalku.com.
"I thought it was a little scary. They were accurate as to my location by about two blocks from my house," she says. "So my immediate response was, what happened, how do you know where I am?"
Once she found out what she was doing, she turned off the geotagging feature on her phone. icanstalku.com has detailed instructions for all the major types of phones on their website.
"We thought it was important to have some idea about these privacy issues," says Pesce. "Going forward we're going to be sharing more information about our lives online and we really want folks to make sure that they know what they're sharing."