You have just returned from a trip to Fiji. You have to check your email of course and surf the net to relax. Suddenly, the ads that you see in your Yahoo mailbox, on MSN, and on Amazon are all about hotels, air travel, and Fiji. Is that just a coincidence? Of course not. It is the result of a specific type of marketing known as behavioral advertising.

Behavioral advertising is an effective way to match consumer-buying patterns with their online browsing patterns. It works like this: the information gathered through Internet data is sold to companies that express interest in a specific segment of consumer online browsing. What is not sold includes names, addresses, or credit card numbers.

In the travel industry the scenario would be more like this: Joe Traveler booked a flight to Australia, he traveled first class, and requested a rental car at the airport. The company buying the information would not know Joe’s name simply that someone using his computer booked that flight and needed a rental.

Expedia admits to using behavioral advertising and calls its program PassportAds. The program is a bit controversial. Proponents argue that no personal identification information is given out so it’s harmless to consumers. Opponents insist that consumers are not well informed about this practice and they may object to it after full disclosure. Where do you stand on this interesting method of advertising?