|It takes a big infrastructure to manage an eBook store. It also takes as big infrastructure to manage selling physical books. and the size of a book(900kb) is

|It takes a big infrastructure to manage an eBook store. It also takes as big infrastructure to manage selling physical books. and the size of a book(900kb) is pretty close to the size of it's amazon product page. |Amazon already has built up warehousing/delivery infrastructure and must maintain it Amazon's retail business shows nice year-on-year growth, and probably can eat the extra capacity left by the book business.