Amazon A9 search engine discount/incentive

MacInTouch Home Page: "I was shopping on Amazon today, and found a link explaining the A9 discount reported earlier. It is exactly 1.57%, chosen because it is pi/2. Amazon's explanation is that it is 'sharing the pi' it gets from ad revenue. It also mentions that you have to keep using the search engine regularly in order to continue receiving the discount (or more likely, simply use it before every Amazon.com purchase)."