Flight to quality. People who already advertise with AdWords will get tighter with their dollars; the percentage of folks foolish enough to just flip the "content" switch rather than pick and choose which websites to advertise on will continue to shrink.
Meanwhile, more dollars that used to be spent on other media will move to AdWords. As Google earnings show, Google is a beneficiary in the short term of the global economic contraction.
For AdSensers, this is a window of opportunity. Not the opportunities of yore, trying to game Google or slap up one-trick ponies for a quick profit, but opportunities for people who act like publishers: providing quality content to readers on the one hand, and relevance to products (read: qualified leads) for advertisers on the other hand.
When I started poking around my left-to-rot AdSense site to see why the payments had started increasing, I was shocked to see a Fortune 500 company targetting me. You can bet I am looking hard at their product line and expanding relevant content.
This is a window of opportunity for little publishers who know how to make quality content and understand the importance of forming direct relationships with advertisers.
The folks who continue to imagine that Google is responsible for giving them traffic or writing them checks, will continue to find life a disappointment.