[Privacy] GPS for your own good
Last year, a UK insurance company tested a "pay as you drive" insurance system that uses a GPS receiver package to track exactly what distance a car is driven and set each month's premium accordingly. It's a sensible idea: If you leave your car in the garage for a month, there's no reason why you should be charged the same as someone who drove 500 miles over the same period. Even better, because the instruments are transmitting (not just recording), if your car is stolen it can easily be tracked and the miscreants apprehended.
The system has some interesting potential side effects. For one thing, the police (or an estranged spouse) could easily subpoena your "travel records" for use in an investigation. The insurance company could also start charging based on where your car spends time: Long periods in high-crime neighborhoods would affect your premium accordingly. Even more provocative, companies could begin collecting data on their customers' driving habits: when and how much they speed, how often they change lanes, their tendency to accelerate rapidly or slam on the brakes, and other features of their driving performance that could (potentially) correlate with accident data.
Really good analytics might even indicate when someone is driving in an impaired state (such as he just saw his latest premium notice and is in shock). But the most intriguing and perhaps lifesaving possibility comes when you hook the insurance company's server to a SPAM phone dialer and arrange for a deep, authoritative, machine-generated voice to call and remonstrate with customers who are speeding or otherwise driving recklessly. (Of course, you'll be able to cut the irony with a knife if answering the phone distracts you so much that…you get the idea.)