Yesterday was my highest Sunday ever i think, and I'm up a few dollars a day on my regular earnings. I think it has more to do with traffic than anything google is doing though.
if you have a 7k traffic a day like me, it is really frustrated when you see your adsense earning is just 1% from the traffic. Lucky that I have fast click and chitika to make up of what I'd lost from adsense.
I would suspect it has to do with september being the end of the business quarter as well as the end of the year for many companies. I am expecting a rebound in the next 2 weeks.
I'd seen the same trend last year. September is my worst earning month for last year and its continue till mid October where CPC start to goes up again until December. Then on January, it will slump again till March. Here is my conclusion base on my 2 years experience with adsense January to March - low cpc April to August - higher, but May is the best month... September to October - terrible November to December - time for you to put adsense all over your site. The best time ever where you'll get the highest payout and normally on December, I will break my records earning per month.
It was not that way for me over the last two years; October turned out to be great and it continued until Mid Feb. Guess it all depends on your area.
Also - Yesterday was a great day, again. The more less performing sites I move to Yahoo!, the better the payout.
yes, its depends on what kind of sites you have I believe. I'm running a desktop customizing and freeware/shareware download site and I believe few people that running the same site as mine, have their revenue slump too.