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. Maybe get more traffic that way. But I think you will have a hard time getting followers if you are mostly promoting affiliate links. If you are using it more for other images and throw a link in once in a while, you may get some traffic to your link tho.