The economy is in the dumps, and President Bush's second tax rebate may do nothing more then soften the blow of a crashing economy. This poor economy has a ripple effect - moving beyond housing and affecting other business sectors and even other countries. Even cities in my area are laying off employees, saying that this is the worst its been since the Great Depression. People feed off these negative comments and clamp down on spending. It's a vicious cycle. Once the economy picks up, companies will start hiring and increasing their advertising budgets. Then everyone, including us, will see increased revenue.
My Adsense earnings have been on a constant downhill slide since December - now constantly earning 1/4 what it was a year and a half ago - even though traffic is much higher now.. The good news is that Kontera has been on a constant uphill move since January, and now regularly earns more than Adsense..
I think it's because of smart pricing applied by the advertisers. I hear that they have strategies to do do so. spend less, earn more...