Small things also. Bezos choose books for amazon since it is a perfect comodity with low consumer prices. You do not have to see the product to know what you will get. Then by using scale of volume they could reduce the sales price and become more attractive. The last step wouldnt have worked, since you are not allowed to sell books at different price in germany. Also if you ordered a book from a bookstore sometimes you had same day delivery to that bookstore or latest next day. Amazon mostly lifted of in Germany when they started to sell other stuff.