"Pinterest has more than 19,744,958 users.
It is the 3rd most popular social networking site after Twitter and Facebook.
Reports say that people are more 10% more likely to buy from a site they found on Pinterest, and spend about 10% more.
Google ranks Pinterest users, and they do it in much of the same way that they do websites – focusing on keywords, quality, and value".
Via Antonino Militello