Slate's Daniel Gross figured that hybrid cars sell to a predictable, easily-identified type: the people David Brooks wrote about in his book Bobos In Paradise. They're the people who used to reliably drive Volvos or Saabs.

But hybrid sales numbers confound that expectation.

As Gross writes, "The rising cost of oil and the current recession, which started among subprime consumers and is steadily eating its way up the economic ladder, may combine to change the hybrid vehicle's image from a white-collar status symbol to a blue-collar money-saver."