Take Zillow Listings With A Grain Of Salt

Zillow has built a business by pretending to be a service for buyers but, in reality, makes its money by selling the buyer's data to subscribers. There is a saying in high technology industries that "if you are not the customer, you are the product." In this case, not only does Zillow sell its readers data as its primary business, but its data is very often inaccurate. How do they get away with that?