The Wall Street Journal reported today that Orbitz Worldwide Inc, the online travel agency, is starting to show Mac users different, and sometimes costlier, travel options than Windows visitors.

The Orbitz effort, which is in its early stages, demonstrates how tracking people’s online activities can use even seemingly innocuous information — in this case, the fact that customers are visiting Orbitz.com from a Mac — to start predicting their tastes and spending habits, the Journal reported.

Orbitz executives confirmed that the company is experimenting with showing different hotel offers to Mac and PC visitors, but said the company isn’t showing the same room to different users at different prices. They also pointed out that users can opt to rank results by price.