Jason O’Grady’s Blog

Philadelphia Enquirer: The practice came to light on a Web forum frequented by DVD fans. One had bought Julie Taymor’s Titus for $24.49, and noticed a week later that the price had jumped to $26.24.

Then he did an experiment: He deleted all the “cookies” on his computer - the tiny files Web sites use to identify and track return visitors. The price dropped to $22.74.

Faced with this and similar tales, Amazon disavowed the practice, and insisted it had just been experimenting randomly with prices.

But consumers and analysts assumed something else: that Amazon was using its ability to analyze data to make more money by charging more to loyal customers and less to those it was trying to lure.