AUDIE CORNISH, HOST:
OK, Robert, it's time for the two of us to talk about a pervasive threat to our online privacy.
ROBERT SIEGEL, HOST:
That's right. It is time to talk about cats. Millions and millions of cat photos have been uploaded to the Internet.
CORNISH: Little cats.
SIEGEL: Big cats.
CORNISH: Grumpy cat.
SIEGEL: And those cat photos can reveal more than just how cute your cat is or how much time you have on your hands.
OWEN MUNDY: I was using Instagram like everybody and photographing, you know, my life.
SIEGEL: That's Owen Mundy, an associate professor from Florida State University.
MUNDY: And it never occurred to me that my phone was geotagging all the photographs with the location and including that information and uploading that.
CORNISH: The surprise drove Mundy to create the website, I Know Where Your Cat Lives. He took pictures publicly shared on photo sites like Instagram and Flickr - photos tagged with the word cat.
SIEGEL: He then used the location data embedded in those pictures to place them on a Google map. And we should say he gathered a million of these cat photos. Well, every so often it's someone dressed in a catsuit.
CORNISH: So when you go to iknowwhereyourcatlives.com, you never know what you're going to see. A different photo pops up every time you visit the site.
MUNDY: You get to see inside of other people's houses. You get to see their cats. And you get to see sometimes them holding their cats.
CORNISH: Mundy says he wants to raise awareness about online privacy and how much information we give out.
SIEGEL: If your cat pic appears on the site, you can remove it by changing the privacy settings on the original photo. Oddly, for a person who created a cat website, he is not a cat person. But he's coming around.
MUNDY: It wasn't when I started. I'm about 50 percent of the way there now, actually. That's an outcome I didn't expect.
SIEGEL: And one other surprise...
CORNISH: People have e-mailed him Mundy not to get their cats taken off the map but put on it.
SIEGEL: Which goes to show you can't herd cats, but you can't herd cat owners either. Transcript provided by NPR, Copyright NPR.