now read this: a crackerjack analysis of circulation declines

Recovering Journalist offers a depressing, but excellent analysis of circulation trends. Well worth a read (preferably with a lot of scotch at hand):

The declines over the past two years are disproportionately large compared to the seven- and 12-year spans–again, despite growing population and, until recently, a healthy economy. In other words, the circulation slide is worsening. It's hard to see, especially with the economy in the tank, any sort of moderation of the downward trend. And that, in turn, chases off advertisers and leads to even more budget-cutting pain.