>It's individuals who make decisions to sell their data in search of convenience. Here's the problem: They're selling your data, too. If you have an average

>It's individuals who make decisions to sell their data in search of convenience. Here's the problem: They're selling your data, too. If you have an average social life, your picture will end up on Facebook. People will click on the little box around your head and put in your name. They may mention you or discuss you in the comments. With enough of that kind of stuff, Facebook knows you exist, what you look like, and where you like to hang out. It can make educated guesses at other things like whether you went to college and where, plus all the things you can derive from pictures like age, ethnicity, and weight. Social networks really are networks, and you can know a lot about a network node from its neighbors.