The copyright protection concerns only "original" creations. A list of categories or products is not an original creation.
As far as it is a "logical" classifying that follows some comment sense, it can't be trademarked and it can be reproduced.
(if it is really original classifying or if it derives completely from the common sense, than it can be considered as "original creation" and thus protected by copyright - but that is IMHO a very rare/unique case - certainly not the Amazon product categories listing)
More about the copyright's scope: http://en.wikipedia.org/wiki/Copyright#Scope