The controversy results after Orbitz found that Mac users spend on average 30 percent more on hotel rooms than Windows users visiting the site and decided on the profiling trial, according to the Wall Street Journal.
The system works by offering Mac users more expensive recommended hotels at the top of searched for suggestions.
Usually Mac or Windows users would see the exactly the same list of suggested hotels, but with the new system Mac users will be shown a modified list of plusher options.
The full list of hotels is still available to Mac users if the choose to search by price rather than recomended options and Orbitz was keen to stress that the price paid for each hotel remains the same regardless of which platform is used to access the site.
According to Fox.com, Orbitz found that Mac users were 40 percent more likely to book a four- or five-star hotel than Windows users, spending on average $20 to $30 a night more than their PC counterparts.
Orbitz confirmed to the Wall Street Journal that a trial of the new profiling method had gone live, but that it was in its early stages.
It's unclear how Orbitz is identifying users, perhaps by logging those using Apple's built-in Safari Web browser.
In Tuesday trading, shares of Apple, in Cupertino Calif., fell 64 cents to $570.14, while those of Orbitz, of Chicago, fell 2 cents to $3.42. By contrast, shares of Microsoft Corp. (Nasdaq: MSFT), the owner of Windows, rose 30 cents to $20.09.