WATERLOO (KWWL) -- We love posting photos of our children and family on Facebook, Myspace or Twitter.
But those innocent snapshots could be revealing a lot more about us than we might've thought, and opening up dangers as well.
Cristina Parker loves taking pictures with her smart phone.
"I like to take a lot of photos of my dog and post them on twitter. Um, I think she's really cute. Also my friends and family," Parker said.
But one day she got an ominous tweet from the website IcanstalkU.com telling her they know where she lives.
"I thought it was a little scary," she said. "They were accurate to my location from my house. So my immediate response was, 'what happened, how do you know where I am?'"
Turns out, Parker's photos contained GPS information called "Geotags," embedded by her smart phone.
Every time she posted a photo online that she took with her phone, she was inadvertently giving out her whereabouts.
"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," Gerald Friedland said.
Gerald Friedland of Berkeley's International Computer Science Institute co-authored a study on the privacy implications of geotagging. The findings: most people had no idea what they were posting online.
"There's enough information out there that you can actually track people and do potential harm to them," he said.
And that's exactly what Larry Pesce wants to warn people about. He co-founded IcanstalkU. com to alert people after he discovered a photo of his child revealed her location. And it can happen to others.
"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 711 and now we know that you're not home," Pesce said.
In addition to potential robberies, Pesce says geotagged photos open up the possibility of stalking and domestic violence. And you don't have to be some expert to get the information.
"Just about anybody that can operate a computer and do a few right clicks could find out someone's location," he said.
Both Pesce and Friedland hope to make more people aware of this potential privacy issue.
"Going forward we're going to be sharing more and more about our lives online and we really want folks to make sure that they know what they're sharing," Pesce said.
So what can you do about it? You don't have to stop posting pictures. Just turn off the GPS feature for photos on your phone. It won't affect the other GPS capabilities.
Parker turned hers off. She now posts her photos without worry. And she hopes others will do the same.
"I don't think many people know they're tweeting their geographic location every time they post a photo," she said.
Since each phone is different, IcanstalkU.com has listed instructions for turning off geotagging for every major brand on their website.
Online Anchor: Sunny Layne