It seems that each day is wildly different in terms of clickthrough rates and earning per click. Some days the clickthrough rate is twice that of other days ... that's not with a small sample, with several thousand impressions per day. Anyone seeing a big variation?
Several thousand impressions isn't all that vast to be obtaining anything all that stable. If it was several tens of thousands of impressions, then I think you would have more of a point, but % CTR can vary by a few just because of a few additional clicks if your dealing with just a few thousand impressions.
My impressions are in the low tens of thousands, and my daily CTR average was quite stable (usually within a tenth of a percentage point) until last Thursday, when it dropped about 3/10 of a percent from the long-term average.
I switched from banners and skyscrapers early Sunday morning, and my average CTR went up again. My new average appears to be 20%-30% higher than my previous long-term average, with only slight variation from day to day.
Revenues are holding up quite nicely. Effective CPM (revenue per 1,000 impression) and average revenue per click show a lot more variation than the overall CTR does, but the bottom-line revenue trend has been up, not down.
The revenue from AdSense is officially in the toilet. I've got far more PSA's than ads now, including sites that had some of the most perfect targeting I've ever seen. Unless something big happens soon I'll be reverting back to ads that were actually generating revenue.
The revenue from AdSense is officially in the toilet.
I'm feeling pretty flush, but not because my AdSense revenues are in the toilet. :-) On the contrary: AdSense continues to perform extremely well on my site.
Obviously, ads and revenues will vary by topic (and, in some cases, by season). It's possible that AdWords advertisers in some categories are opting out of "content ads" at a greater rate than average.