Through Marriott.com, the Bethesda, Maryland-based lodging company sold $3.7 billion worth of rooms in 2006, more than doubling revenue from the site in 2004. For the first half of 2007, Web sales for Marriott hotels, which range from luxury Ritz-Carltons to lower-priced Fairfield Inns, were up almost 25 percent.

To attract guests, Marriott created incentives to book through its Web site, awarding points that can be redeemed for free rooms. The points can't be earned on third-party sites like Hotels.com and Orbitz Worldwide Inc.'s Orbitz.com.

"In 2001, 2002, the question we got from the press was whether Hotels.com was going to put us out of businesses," Marriott Chief Financial Officer Arne Sorenson said in a March interview. "It took a few years but the question became, 'Are those guys going out of business?'"

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