A WebmasterWorld thread has someone asking if what Amazon is doing, is considered cloaking. First let me show you what they are doing.
Go to this page on Amazon.com. Notice, at the top right of the results is a "Sort by" drop down. Here is a picture:
Now, go to the Google Cached version of that page:
Yes, it is not there. It seems like Amazon served Google the page without the sorting feature, which technically is a form of cloaking. But is this done with intent to artificially boost their rankings?
The content seems exactly identical, minus just the sort by feature. The sort by feature can produce duplicate content and make it harder for Google to index the incredibly large site. Is this being done in a way that is trying to hide something?
If they really want to be white on white - they could now keep the sort by there and use the canonical tag for all the sort by options. But this might be something Amazon has doen for years prior to the canonical tag coming out?
Personally, I wouldn't consider this against Google's cloaking guidelines, but I am not Google.
Forum discussion at WebmasterWorld.