To a certain extent, Amazon's retail presence is 68% Marketplace (from the article). Marketplace is really just a very high scale website plus very high scale order fulfillment which nets an analogous 6%-15% fee for listing, inventory storage and shipping/returns.
If I were say, Procter and Gamble/Clorox (Consumer Staples), Macy's (Consumer Discretionary), Visa/Fedex (E-Commerce), Aetna (Healthcare) if I were going to look at options for cloud, would I host my enterprise on Amazon who is actively trying compete with me and provide the end customer with alternatives to my product/services? Or would I go with a vertical pure play cloud services provider like Microsoft.
http://uk.businessinsider.com/amazon-ad-business-to-reach-5-...