Mac users get pricier Orbitz offerings? Sometimes Windows users do, too.

For some time now, the Wall Street Journal has been running a series on how personal information gleaned from users’ online activities can be used to shape digital marketing. The concept that site operators can personalize marketing messages on the Web is not earth-shattering – all advertising-based sites do it, including wsj.com – but users aren’t always aware of the extent of the practice.

In an item posted Monday night, the Journal reported that online travel site Orbitz.com has been experimenting with showing users of Apple’s Macintosh computers pricier deals than their Windows counterparts. The reason: Research shows Mac users tend to spend $20-$30 more per night on hotels than Windows users.

Now, there are several caveats here. First, Orbitz honchos say they aren’t showing the same rooms at different prices. Instead, Mac and Windows users sometimes see different featured deals. And, if users sort a list of hotels by price, they’ll get the same list, regardless of their computing platform.

Some examples of the practice, from the WSJ story:

. . . A Mac search for a hotel in Miami Beach for two nights in July displayed costlier boutique hotels on the first page of results, such as Sagamore, the Art Hotel and the Boulan South Beach, that weren’t displayed on the PC’s first page. Among hotels appearing in both searches, some pricier options (such as the $212 Eden Roc Renaissance and the $397 Fontainebleau) were listed higher on the Mac. Overall, hotels on the first page of the Mac search were about 11% more expensive than they were on the PC.

Similarly, hotels on the first page of results for Baton Rouge, La., appeared in different order for Mac and PC and were 13% more expensive in aggregate for the Mac search.

Curious about this, I decided to see what Orbitz’s hotel offerings look like from the Mac and Windows perspective. Since I run Windows on my Macs in a Parallels virtual machine, I can call up Orbitz and compare two lists of hotels for the same city in Windows and Mac browsers, side by side.

What I found is that the list of hotels you’ll see at any given time may vary. Searches I conducted Monday evening were different than those I did this morning, on both platforms.

But I also found that, sometimes, Windows users are offered pricier deals than Mac users.

For example, I’m taking a vacation later this summer that will have me spending a night in Montgomery, Ala. I did a hotel search this morning for a one-night stay in that town. I used Chrome for Mac and Chrome for Windows 7 to do the searches, and didn’t log into an account, viewing the site as a guest.

The first three items in a search on Orbitz are the same. In Windows, the fourth is a Wingate by Wyndham hotel for $84. On the Mac, it’s a LaQuinta for $52.

    orbitzwin  orbitzmac

Online retailers experiment with showing different users different pricing all the time. Amazon is famous for doing this – or infamous, if you happen to be get a more expensive deal than your neighbor. For example, complaints about this on the online retail giant’s site date as far back as 2000.

Still, Mac users of Orbitz may want to sort their search results view by price rather than “Best Values” to make sure they’re seeing the best deals.