From AdAge : [...] Pinterest doesn’t see itself as a social media platform. It is not an alternative to Facebook, Twitter or Instagram for consumers or marketers. It is positioning itself in the world of Google and search.
Pinterest is, at its core, a tool for indexing the visual web, much like Google’s roots as a tool for indexing information and meaning on the web....[...] It is looking to help people find fulfillment through newly discovered "things" they love, which can then lead to real-world action and purchasing. It's about demand generation instead of demand fulfillment.”