Innovation in e-tailing

Over the last week ( 12/2 - 12/9) I've been tracking Amazon's bestsellers in the HDTV category. To my surprise, I discovered that prices for most popular TV sets sold and shipped by the e-tailer fluctuate over time. For example, the price of Samsung's LN46A650 HDTV varies from $1,499.99 to $1,614 ( see the graph below).

I wonder if they run some kind of a reverse auction to maximize revenue from the holiday traffic.