why not link to amazon as your title?
I've seen this happen on a very popular site, design-by-committee was responsible. It looks like amazon has the same problem. They ask designers to design something nice, but the requirements are insane - you have to shove 20 different blocks on a given page. Then they go through rounds of discussions in rooms full of project managers, product managers, designers, project leads, and often some executives (who for sure think they know better). They argue over and over, of what features should be on the page, while stabbing their political opponents' suggestions. It ends up in a clusterfuck like that.
EDIT: That's what it looks like to me:
Above the fold: http://i.imgur.com/X0xde.jpg
Below the fold: http://i.imgur.com/ldzIj.jpg
Here's how the page for a single book looks like when comparing Amazon's with my own CSS: http://imgur.com/a/lhWr5
Yes, it's the same page.