Check out this article about Adsense in the financial crisis and also make sure to read this thread on digitalpoint.
My traffic continues to increase and and revenue is increasing. Slight dip Christmas and New Years. Excellent January, and February is looking very good. I've also booked in a couple individual advertisers that I didn't expect - Several companies called and bought ad space in January and all my current ad clients told me in January that they want to continue 'indefinitely' (my minimum is 3 months and a couple have 1 year ad contracts with me already). I was expecting 3 ad clients to cancel, but they said to keep the ads running. I don't know what's happening out there, and I'm ready financially for a total collapse of adsense, but so far things are looking good. I think it all depends upon what a person's niche is.
Google is just not very nice to Adsense publishers. Paying 5-10 cents for ad clicks that cost around 3$ for advertisers (Estimated by traffic Estimator). I used to get 1$ per click in 2006 when the displayed ads cost around 2.5$.
This isn't 2006. The times, they are changin'. Every news feed I read, another group is getting their paycheck cut. To play on the internet is no different. There are other options to AdSense. If you are dissatisfied, try another option. I'm doing quite well and have no complaints.