The project started around December 2009, with the actual closed-beta service commencing March 2010. And, which till date is still an invitation only service.
Pinterest is unique from the fact that it has reinvented the 'image worth's more than a thousand words ideology', as pioneered by David Galbraith's Project Wist in 2005. Albeit, the social web phenomena has not taken-off, which may be the reason for the project's failure.
Pinterest is simply put as a 'visual bulletin board', bringing the beauty and power of images to live to convey specific message on the social platform. It is more related to Twitter in functions, and employs similar terminologies: Pin (is an image uploaded on Pinterest), Repin (is the equivalent of retweet), while Board (is a collection of pins).
There are varied interests and topic boards which are open for users to follow, and that reflects the updates on the home screen. Each image board contain items of media, known as pin, which may be a picture, video or related media stuff.
Pinterest, similar to other social networks, allows a user to follow the activities of other users, receiving updates on the Homepage through 'Pin Feed'. And the high point of the service, is perhaps, the ability to convey a vivid picture of events as in wedding, than words can relay, more reason the feminine folks are trooping en masse.