Most markets follow a Pareto distribution where roughly 20% of the customers generate 80% of the sales. In this case, that would suggest that 20% of the book buyers buy 80% of the books sold.

Dilger may be correct that most users don’t read enough ebooks to justify the purchase of a Kindle. However, frequent readers may see a value in the device. If penetration is high among the most active book consumers (20% of the total) then this could translate into well over half of the books sold.

If Amazon’s goal is to sell books (not readers) this could be good news. They only need to sell a few low margin reading devices in order to capture the bulk of the market for books.