Netflix data shows shifting demand down the Long Tail
A team at Wharton did some Long Tail analysis on the Netflix ratings data the company released for its Netflix Prize. Although I don’t agree with many of the conclusions in their paper (like some other academics, they got confused over definitions of “head” and “tail” and fell into the common trap of doing percentage analysis in an absolute numbers world), the data was interesting. They kindly shared it with me before publication and incorporated some of my analysis in their paper. But for some reason they didn’t use the best part, which was this chart:
The vertical axis is percentage of total demand (with ratings used as a rough estimate of rentals), and the horizontal axis is the popularity rank of the DVD titles. Between 2000 and 2005, the Netflix selection grew from 4,500 DVDs to 18,000, and the effect on the demand of this increase in variety is shown above.