When money gets a bit tight it's not surprising if businesses start to cut back on discretionary expenditure and advertising is going to fall into that category. That sort of cutback will be restored when business picks up.
What's very likely worrying Google senior management is that their customers' senior management might start asking harder questions about advertising policy. Questions like "Does tacking really pay off? How much money are we spending showing adverts to somebody who once enquired about $PRODUCT, who's then bought it, isn't going to buy another and is more and more unhappy about having pointless ads shoved in his face?"
When those sorts of questions start to get asked Google's allegedly value-added services start to get questioned and that might be a hit from which it will be far harder to bounce back.
Biting the hand that feeds IT
