My observations are that I am seeing a drop in CPC, clicks and requests are fairly stable at my end. Had the lowest earning day ever yesterday!
Why do I think this is happening?
The latest updates don't help, by giving people exactly what they want, and not what they need in the search results there is little reason for surfers to click an ad.
Revenues of advertisers are being squeezed. 4 of my clients have pulled their adsense campaigns mainly due to the drop in traffic from the organic results, 3 have pared back their spend.
So we have less advertisers, paying less money and Google sending people directly to relevant sites giving users less of a need to click on the ads.
My personal Adsense revenues are now so low I'm running at a loss and will be pulling the plug on a few sites soon for purely financial reasons.