With people worried about on-line privacy, it's easy to forget how much invasion of privacy takes place when you shop at a store. Unless you pay cash and don't use a discount card, stores keep track of what you buy and sell the information to brokers to in turn sell it to other businesses.
Here's lede of a New York Times Sunday Magazine article on the subject:
Andrew Pole had just started working as a statistician for Target in 2002, when two colleagues from the marketing department stopped by his desk to ask an odd question: "If we wanted to figure out if a customer is pregnant, even if she didn't want us to know, can you do that?"
It just gets more chilling from there. For example:
The desire to collect information on customers is not new for Target or any other large retailer, of course. For decades, Target has collected vast amounts of data on every person who regularly walks into one of its stores. Whenever possible, Target assigns each shopper a unique code - known internally as the Guest ID number - that keeps tabs on everything they buy. "If you use a credit card or a coupon, or ﬁll out a survey, or mail in a refund, or call the customer help line, or open an e-mail we've sent you or visit our Web site, we'll record it and link it to your Guest ID," Pole said. "We want to know everything we can."
Also linked to your Guest ID is demographic information like your age, whether you are married and have kids, which part of town you live in, how long it takes you to drive to the store, your estimated salary, whether you've moved recently, what credit cards you carry in your wallet and what Web sites you visit. Target can buy data about your ethnicity, job history, the magazines you read, if you've ever declared bankruptcy or got divorced, the year you bought (or lost) your house, where you went to college, what kinds of topics you talk about online, whether you prefer certain brands of coffee, paper towels, cereal or applesauce, your political leanings, reading habits, charitable giving and the number of cars you own. (In a statement, Target declined to identify what demographic information it collects or purchases.) All that information is meaningless, however, without someone to analyze and make sense of it. That's where Andrew Pole and the dozens of other members of Target's Guest Marketing Analytics department come in.
Update: Whoops; left out a link to the article! That's been corrected.