The ad-supported site also offers historical value
changes for homes in chart form; historical value changes for homes as compared
with the surrounding ZIP code, city, state or country; all comparable home sales in an
area; and satellite, aerial and parcel views of homes.

Users can also create confidential personal
worksheets on individual homes and use a tool that lets them refine the value of
a home based on changes or additions to that home, such as a kitchen remodel.
The tool calculates the remodel value for the area based on local remodel data
and depreciation.

The site does not
require users to enter any personal information and promises that no one will
contact the user.

Zillow.com, the name
of which comes from the word "pillow" and the notion of zillions of pieces of
data, was founded by Expedia founder Rich Barton and former Expedia senior vice
president Lloyd Frink. It has raised $32 million in funding from Benchmark
Capital, Technology Crossover Venture and other private investors.

The Web site was inundated with traffic and
inaccessible on Wednesday, but it was expected to be reachable later in the day,
a Zillow representative told CNET News.com.