It shouldn't work but it does. All too well.
Amazon's site breaks the rules.
Crowded over heavy navigation width and long funnels to purchase; key product information out of view and requiring extra customer effort; product recommendation that lacks sophistication and referral power.
But I know that when I visit the site they will almost always have what I need. And I will be ready to purchase there and then. It's the zero moment of truth and all helped along by one-click purchasing.
So here's something for Amazon. I know what I want before I arrive on your site. I have trust in your sales and delivery process. I know I will find it on your site cheaper than most other sources, online and offline. So give me two just two minimal features. Smart semantic personalized search and a simple immediate purchase button. That's all I need. Bare bones ecommerce, working well.