Pinterest is a photo sharing and social media website that allows users to save or "pin" images and follow other users with similar interests. It was founded in 2009 by Ben Silbermann, Paul Sciarra and Evan Sharp and is headquartered in San Francisco. The site grew rapidly after its launch, reaching millions of users by 2011. While Pinterest provides a unique way for users to explore visual interests, it also faces challenges around spam and legal issues regarding the use of pinned photos.