If we are not comfortable with our personal information ending up in the hands of third-party entities for the ostensible aim of improving national security, why we would be OK with having such data available to third parties to help them figure out more ways of selling us stuff?

Yet companies are developing ever more sophisticated methods of harvesting personal data, as I wrote back in January. Microsoft, for instance, has applied for a patent for a system of sensors that would gather information about customers as they make their way around a store, analyze the data, generate profiles and serve up targeted ads to those customers. As with most developments of this type, Microsoft makes this out to be practically a public service, with one of its executives saying it's about "making the shopping experience better for the consumer."

Yeah, right. I think it's a stretch to assume that people will appreciate targeted advertisements. As I wrote in my blog, targeted ads are a bit like an appendectomy. There's no way of avoiding them, but anesthesia (or relevance, in the case of advertising) makes the experience somewhat less painful.

I've recently encountered several such high-tech methods of marketing, including a surveillance mechanism that tracks shoppers' behavior by monitoring the signals produced by their cell phones. The system has already been installed in two shopping centers in the UK, reports Times Online, with three more slated to begin using it next month. One of the malls added German signage after discovering that a high percentage of its visitors were German. (Yes, the system can tell in which countries the phones are registered.)

Path Intelligence, the company that developed the technology, downplays privacy fears by pointing out that it cannot link the information it gathers to phone owners because only the telecommunications network can match a phone's unique identifiers to the person who purchased the device.

Even more invasive are the brain scanning technologies developed by NeuroFocus and EmSense Corp., which study brain activity, skin temperature and other physiological factors to determine how folks react to ads, computer games and other stimuli. Both are leaders in the emerging field of neuro-marketing, reports SFGate.com. Science laid the foundation for neuro-marketing with research that studied the brain to better understand attention deficit disorder and Alzheimer's disease.

The two companies pay people to watch commercials, wire them with sensors and record their reactions. NeuroFocus, which just got an investment of undisclosed size from the Nielson Co., charges $50,000 to $1 million for its analytics, depending on the subject of the study and how many people must be tested. ESPN employed NeuroFocus to determine whether sponsor logos were noticed during newcasts, a question that an ESPN exec says would have been difficult to answer using survey research. ESPN then tweaked logo placement to improve viewer attention and retention.

These neuro-marketing methods promise to be more effective than surveys, focus groups and other traditional types of market research because people don't always know what they are thinking or may not be willing to honestly say, writes Nick Carr in The Guardian. Carr questions whether companies will be able to use this knowledge to control consumer behavior in increasingly subversive ways. He writes:

If it achieves even part of its potential, neuro-marketing promises to tip the balance of power in the marketplace from the buyer to the seller.