onlineleben - 9:09 am on May 29, 2013 (gmt 0)
Now is starts to get interesting.
They are on the lookout for affiliates themselves. By using your amazon code they triggered your interest in their site (which caters a niche you are expert in). Your research to find them tells that you care for your web properties and don't just throw up sites full of ads. You are probably a good candidate to promote their ebook.
Give it a try and check what happens to the affiliate links with your code after you have signed up for their program.
OTOH, analyze why they make money with amazon in your niche and maybe adapt the concept.