Zillow.com: Very cool tool with some obvious benefits. Zillow is a property valuation search engine with map based tracking of home and property valuations across the USA. Though I do not visualize the revenue stream yet, realtors and realty marketing folks should find this tool not only useful for research but also find a niche marketing platform for sellers and buyers. I sat there and checked out every property I have owned in the past and the present. The numbers seem to be a tad off, but that is to be expected.