What a fun article:

iPod sales sales have slowed considerably. They were up only 8% in the quarter. to 10,644,000.

This use of statistics serves as a wonderful idiot detector. The idea seems to be that if any derivative of a function is negative at any time, the entire function will soon be zero. In other words, any function that grows more slowly than e^x is doomed. But, as I know I’ve seen somewhere, probably applied to the housing market:

Anyone who believes in continued exponential growth in a closed system does not understand the problem.