A photo and video-sharing social networking site based upon a pinboard metaphor. Users can save photos and videos (known as pins) on pinboards that are generally organized by category. Other users can then follow boards that interest them.
Pinterest began in 2009, launching as a private beta with 5000 users. By early 2010 it was growing about 50% per month. In 2011 usage began to grow almost exponentially, fueled in part by the release of the Pinterest iPhone app.
By July 2013, Semicast was estimating that Pinterest had over 70 million users. Current estimates are that over 80% of those users are women.