Pinterest is one way to get traffic because the image on them is easy to go to the top of search engine; besides, it helps u to get more organic backlinks 'cause the links are nofollow.
I have used Pinterest for my blogs, but I am not sure that it would go over well with affiliate marketing. For the most part people are on Pinterest to see cool pictures, pretty pictures, amazing pictures and so on. Now if you have a blog with pictures, you can link your blog to Pinterest and have your affiliate marketing done through your blog.