Two new real estate websites are starting to offer services that could change the way real estate is bought and sold, writes the New York Times. Just-launched Zillow.com helps homebuyers and sellers obtain detailed sales data that real estate agents typically do not display in the public multiple listing service. Last week, a smaller site, Redfin.com, introduced a service that automates the process of bidding on a house online.

Zillow has a higher profile because it has obtained $32 million in venture capital financing and its chief executive, Rich Barton, was a creator of online travel agency Expedia.

Many real estate agents worry that sites like these could be a first step in an online evolution that could threaten their $60 billion commission-based business, just as Expedia, Travelocity and others have reframed the travel business.

Barton said it was not his intent to take away any part of real estate agents' commissions. Instead, Zillow is an advertising-supported site.