For John Q. User that has a website, linking to Amazon and making a little bit of money is not difficult. There’s a bit of stuff to download and stick in the site, a couple of links, and you’re off.
For a website owned by a corporation Amazon requires greater participation, including putting Amazon’s ads on pages and salting all pages with links to Amazon inside of your text content. In effect Amazon cuts itself in as a partner in your business. They may pay you for it – if they decide you’ve done a sufficient job of linking and etc., if not sufficient by their standards they just refuse to pay you anything – it’s practically a full time gig all by itself. Not worth the effort.