Tactful Targeting?

Today's Wall Street Journal has a fascinating story about how some online retailers vary pricing and offers depending on an individual shopper's behavior (which key terms you use to search for products, what time of day you browse, whether you've shopped there before, etc.).

In other words, you and I might see a different page/price/offer when visiting Overstock.com or Delightful Deliveries. Do I really want to find out that I paid shipping fees for that MP3 player I bought when my sister got free shipping for buying the identical product on the same day from the same site? What happens to the retailer's reputation once word gets out? Ouch.

As a marketer, I'm all for targeting. As a customer, I want targeting that benefits me. Tactful targeting might be a compromise: the idea that based on my real-time behavior (such as switching back and forth between two products before going to the checkout page), a site would offer me something to encourage me to buy now.