“A similar report Wednesday showed oil, gasoline and other fuel supplies unexpectedly rose sharply. Traders saw both the petroleum and natural gas reports as reasons to sell, as they reinforce data that show consumers are cutting back on their energy use.”

-http://biz.yahoo.com/ap/080717/oil_prices.html

It would seem that oil being so expensive encouraged people to use less.
Huh, the laws of supply and demand seem to work. Imagine that.