They found that quasi-random ordering increased sales? That seems odd. What algorithm do you suppose they're using to order results? Random number generator?
If anyone in the existence of the Internet was best suited to experiment with sorting, it would be amazon. A 1% improvement for amazon pays for a department of engineers.
A department of engineers that can experiment with advanced search.
In the article's example, 'ipod', I think amazon's strategy is clear. They are sorting lowest to highest of what they think you might mean by 'ipod'. Does the user mean 'ipod [touch]'? 'ipod [nano]'? Or maybe 'ipod [accessory]'?
If they did the 'proper' substring based search to create a set which was then ordered by price you would only see ipod accessories for the first 100 pages. Which would be prefect if 100% of people who searched 'ipod' only wanted accessories. Which is not the case.
So amazon is 'cheating' to show users what want to increase sales, even if it drives us engineers up the wall.
