Phone Metadata Can Tell What You Do As Opposed to What You Say

“That’s because a phone call—the metadata of a phone call tells what you do as opposed to what you say. So, for example, if you call from the hospital when you’re getting a mammogram, and then later in the day your doctor calls you, and then you call the surgeon, and then when you’re at the surgeon’s office you call your family, it’s pretty clear, just looking at that pattern of calls, that there’s been some bad news. … One of my favorite examples is, when Sun Microsystems was bought by Oracle, there were a number of calls that weekend before. One can imagine just the trail of calls. First the CEO of Sun and the CEO of Oracle talk to each other. Then probably they both talk to their chief counsels. Then maybe they talk to each other again, then to other people in charge. And the calls go back and forth very quickly, very tightly. You know what’s going to happen. … Now everybody carries cellphones with them. And so, the data is, when I call you, I know that I’m talking to you, but I have no idea where you are. It’s the phone company who has that data now. And that data is far more revealing than what’s on the outside of an envelope [sent through postal mail]. As I said earlier, it’s what you do, not what you say. And because we’re carrying the cellphones with us and making calls all during the day, that it’s very, very revelatory. … In fact, all it takes is four data points to be 95 percent sure who the person is. I noticed President Obama said no names, but in fact, if you know four locations, because home and work are often unique pairs for most people, 95 percent location of—of times when you have four location points, you know who it is you’re listening to. So, you follow somebody, and they make calls from work every day, and then one day you notice they’ve made some calls from a bar at the end of the day. And then you discover somebody in middle age, somebody who ought to be working, is now making calls only from home. You know they’ve been fired, even though you haven’t listened to any of the content of the calls.”

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