I'm trying to gauge how valuable my data is. I have a database of over 1 million current US real estate listings complete with agent info and local school data with more listings being added and updated daily. I'm working on building an API to access this data for a few friends to share with me but I'm curious to know how this data could benefit white hat SEO? How does Google treat real estate listing web sites? I'm thinking about launching a few sites powered by the API. Each site could potentially have over a million pages each with minimal work. Any feedback would be appreciated.