there are maybe hundreds of similar threads like this in DP.. and the answer is Yes..economy is down and we are all affected..
My technical sites were down in during the holiday period but are now as before ... maybe even better .S.
umm my traffic has gone up 1000% but my earnings have only gone up 25%. so 10 times as much traffic and 1.25 times orginal earnings. im pissed!
Traffic gone up very much but earning didn't with that ratio, But can't blame the economy only may be some other reasons. May be some of them related to how we position ads on pages and how much ads we place on page. As according to Google ads down in source are more likely to earn less in compared to ones which come on first place and stuff.