Its probably gone down because people don't want to pay so much for advertising anymore because of the recession
My adsense revenue dropped by a couple percent last week however I managed to boost it again and im earning $40 per day which is not bad.
Probably because advertisers have scaled down their budget or big G is shoring up its own revenues by cutting a bigger pie off publishers.... Regards, RightMan
I've done pretty well this month so far! Things are going are looking up I think. But then again I am testing the code on more sites now that have more traffic. Don't worry .. Google isn't going anywhere anytime soon! They are the giant when it comes to Search Engines.