Today, I was just checking my amazon site stats in google webmasters account, and got a hint that I got a backlink from ebay. I didn't believed this at first, then I confirmed it, a seller on ebay, referred to my site, as a source to get more information about the product. Now, don't ask me what the product was! Don't wanna disclose the niche.
And, now I am wondering, if manufacturers can add links to third party sites for reference under product description on their Amazon product listing? I am not even sure, who manage the product listing on amazon, seller, manufacturer, or amazon itself.

Any answer?