Reading this question about the best e-commerce check out flow, I wondered, "What Would Amazon Do?" For instance regarding the check-out process, most people agree that you'd prefer an inline tip about adding an element to your cart to being redirected to a separate page. Yet Amazon does the latter, and surely they do that with good reason, being the largest e-commerce site on the Internet.
I wondered this, and then wondered the following: where can I find more information about how Amazon makes UI decisions? Are there any books? Blogs? Whitepapers? I've seen things here and there over the years, but there's not really any go-to resource (which suggests a market niche that needs filling, btw).