So this topic made me curious, were does the first tab in the tab chain on Amazon go? I loaded the page in firefox, hit tab, and saw the first tab was http://amazon.com/access
Ok, this is an interesting design choice. That access link goes to a page with minimal styling, probably optimized for screen readers.
Now I'm really curious, and I pop open NVDA to give the page a listen. After the page title was read, the access link was read, which was very helpful: "A different version of this web site containing similar content optimized for screen readers and mobile devices may be found at the web address: www.amazon.com/access". It would have been best if Amazon did the work to make their default site screen reader accessible, but this is a nice alternative to having no accessibility at all.
Amazon needs to do some html/css/script minification on their homepage! Oh, nevermind, they gzipped it. :)