Lots of comments on this today in the press. One I haven't seen: Perhaps Amazon is starting to emulate the wholesale club model. That is, maybe they are trying to see if they can clear a profit on membership fees and simply break even on merchandise sales. It has certainly worked for Costco.

Bezos believes strongly in driving sales growth and cash flow through low prices, mainly by offering free shipping on most transactions.

Bezos reinforced that belief on Wednesday by announcing yet another shipping promotion, Amazon Prime. For $79, customers can get express two-day shipping on all purchases for 12 months at no further cost.