My daily revenue for sites have been decreasing lately. Usually my average has been about $10/day. Lately is is down to $3 - $4 / day. Traffic and SERPS have remained the same. Are other people seeing the same?
I have a strong suspicion that it has to do with you ctr and conversion rate. This has affected your quality score provide by adsense that they have to reduce your payout. At the end of the day the advertiser are the ones who are paying google and if they aren't converting on their end their not going to continue paying google.
well, may be people were clicking your low paying ads...! High paying ads are arranged to top of the every adunits.. so dont put too many ads close and give them always a chance to click on big rectangle ads and you will get your CPC increased as well as Your earnings and CTR
I've noticed the same thing.. income decreased to only 50% of the original amount. Impressions & CTR didn't change much.
Go to your account options and opt out of "Interest-based ads" then save. Give that a go for a week and see if it makes a difference.
There are big factors involved on your earning per click - Geo-location of visitors and the advertisers. If high paying advertisers do specific for visitor from US to see their ads and your visitors are not come from US. Your ads will be displayed from lower paying advertisers instead. I would recommend you checking out the displaying ads based on your visitor location. Inspect them each by each to see some lower quality ads and filtered them out. Most of these advertisers tend to drive traffics from your website to their MFA site just for arbitrage purpose. They are also tend to pay at least at possible, that why you would earn like nothing from these advertisers.
This is the depressing answer to the lower earnings problem. Read it and weep. I am. http://www.webmasterworld.com/google_adsense/4123174.htm