very nice. made about $600 on pinterest this way before they started replacing affiliate ids. nice idea with using curated product lists, i was grabbing random products from a few selected categories (clothing, electronics, sports equipment, etc.) using amazon's own product advertising api. right now selling "user-friendly" GUI tools to do this sort of thing on "black hat SEO" forums seems to be a more lucrative business. i used my own python script which i later ported to c# for better threading support (this was before node.js was cool).
bitly won't work. pinterest follows and "strips" redirects to generate link title and thumbnail. you need to have your own url shortener with pinterest's crawler either blocked or served different content. an interesting idea would be to host the links on a domain/service they can't easily block (i.e. tumblr) and do the redirect to amazon using javascript.
