Real estate startup Zillow.com will provide Yahoo with satellite map-based search functions and home-value tracking.

Yahoo and Zillow, still in beta mode, have struck a deal to allow visitors to Yahoo Real Estate to use Zillow's software to look up and compare approximate real-estate values, reports CNET. Zillow also provides information on value fluctuations over the previous week and charts of changes stretching back a year.

Data on more than 65 million homes is available, but none in some states (e.g., Indiana, Texas and Louisiana) because of nondisclosure laws, while other homes are simply not yet in the database. Seattle-based Zillow uses a proprietary formula based primarily on public records to generate its "Zestimates" of homes' approximate market values.