This is also true of search engines, social media, and various other interactive systems. Google's initial search-algorithm breakthrough was the realization tha

This is also true of search engines, social media, and various other interactive systems. Google's initial search-algorithm breakthrough was the realization that they had a massive source of data for search result correctness in the form of the behavior of users querying their site. In general, it's wise to assume that all web interactions are a two-way street between the user and the service provider.