one of my sites lost excellent search rankings a couple weeks ago.. since than of course traffic is down, but i have also noticed the per click earnings is greatly down.
this is very true and it will start to get worse as time goes by, less money going in, and more webmasters trying to make a dime as the year goes by and into next year it will be harder and harder to make 10 cents a day
when crisis strikes people spend less on something they dont fully understand. google contextual ads have become so versatile these days that folks don't fully get it. it doesnt help that quite often you can't track down your conversions to a specific adsense site - if you use "entire content network". even custom google analytics filters dont help as the referrer is often http://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-XXXXXXXXXXX or something search ads are simpler so when people have to shrink their budgets they keep simple stuff and reduce "complicated" stuff