Here’s why companies like Amazon and Google share their APIs with developers : “In a way, Amazon and Google are outsourcing their user interface development, with the developers working for free. In exchange for letting others easily access their data, these companies perpetuate their brand, spread good vibrations through the developer community, and allow others to experiment with all kinds of innovative solutions without taking on any risk. In turn, the developer gets to act as the portal to Google’s/Amazon’s data, thereby benefiting through the advertisement for whatever tangential services that they offer.“ ( via Tim O’reilly )