The reason, per a report in The Wall Street Journal, is because of research by Orbitz indicating that Mac users often spend as much as 30 percent more on hotel rooms. Orbitz confirmed the practice to the newspaper, but indicated it was being conducted on an experimental basis.

Macs and Five-Star Hotels

The travel company said that it was showing different hotel offers to Mac users, not the same rooms at different prices, and it pointed out that Mac users, as well as others, can rank results in order of price.

With the site's average hotel room price being $100, $20 to $30 more commonly spent by Mac users is significant. Orbitz chief scientist Wai Gen Yee told the newspaper that Mac owners are about 40 percent more likely to choose a four- or five-star hotel than Windows users, and that, in the same hotel, Mac owners are more likely to stay in the pricier rooms.

Orbitz indicated that, while it is trying out this kind of you-are-your-platform targeted search results, other factors are more important, such as a customer 's location, history of purchases and searches on the site, and a hotel's promotion. Orbitz competitors Expedia and Priceline have indicated they don't send results based on assumptions made from a customer's operating system.

This kind of price differential by platform may help Orbitz have a better year than it did in 2011, when it lost $37 million, but it raises questions about whether predictive analytics -- which looks for trends in data that will help to forecast customers' buying patterns -- could end up working against the interests of some customers.

Tip of the Iceberg?

The Orbitz experiment could be only the tip of the iceberg.

Forrester Research and Shop.org recently released a report noting that tablet owners tend to place larger online orders than owners of laptop or desktop computers. Apple's iPad is, by far, the leading tablet. And IBM has found that iPhone owners are bigger spenders than owners of Android or BlackBerry phones.

The fact that Apple device owners might, on average, have more disposable income than owners of other devices will come as no surprise to anyone who has compared Apple prices with others.

But a large reason the story is attracting attention is that personalized, targeted marketing and advertising has, to this point, largely been presented as an unalloyed benefit to the user -- directing their attention to products and services that are most likely to be of interest, or providing the best prices on similar items.

As the reams of data about any given Web user accumulate and point to a more refined profile, the question may become whether the online universe of "deals" presented to that visitor represents the actual reality in the marketplace -- and if the pricing shown is in the user's best interest, or the seller's.

Kevin:

Regina: