In the vein of data collection . . .
. . . every had your ID scanned to "verify your age" in a club or restaurant? I'm sure you have or know someone that has. As with anything else with a magnetic stripe, the mag stripe contains more information than just your birthday (that's why you can check in at airline kiosks with your credit card or your driver's license). Imagine the potential information that could be captured from a mag card swipe at a restaurant or bar -- demographic, consumer behavior, direct marketing (i.e., address), etc. Wired had an article today regarding this new trend. The Wired article also directs you to a website called Swipe, which provides a toolkit that allows you to decode barcodes, calculate data, etc.