Note from Jimmy Hua: This is quite an interesting idea. If you really thing about it, with geotagging, you can figure out where someone took a picture and you know when they did based on the creation date of the photo itself. With a large enough database of photos and associations of who took the pictures and who is in the pictures, you can figure out who knows each other. You can see that where there are overlap of individuals in different pictures in the relative time frame. Which means even though two people aren’t in the same photo, they may know each other if a person in common takes a picture with both of them in a relative time frame. You can also incur other information with this knowledge and information. The only time in which this is not true is a huge event where random people are in pictures and taking random pictures with other people.
This post is shared through my Google Reader from another source. All credit of the post belongs to them which you can access by going to Geotagging Reveals Not Only Where You Are, but Also People You Might Know
Cornell University researchers have found that when comparing photos posted on the Internet, as few as three co-locations could predict that two people posting different photos were socially linked. The researchers say their results could have implications for online privacy. They used Flickr’s photo-sharing Web site to access about 38 million photos. Users label their photos with the time and place they are taken and some cameras automatically add this information to the photos with built-in global-positioning systems. When two people posted several pictures from the same locations and at around the same time, there was a good predictor that those people would have a social network connection, according to the researchers. “It’s not that you know with certainty, but it’s a high likelihood that these people know each other,” says Cornell’s Dan Huttenlocher. Similar conclusions could be drawn reached from credit card purchases, fare card transactions, and cell phone records, the researchers say. “While it’s obvious that a photo you post online reveals information about what is pictured in the photo, what is less obvious is that as you post multiple photos you are probably revealing information which may not be pictured anywhere,” Huttenlocher says.
From “Geotagging Reveals Not Only Where You Are, but Also People You Might Know”
Cornell Chronicle (12/08/10) Joe Schwartz