You said, “I have a theory now that Google is just messing with me. As soon as I make changes to adsense there is a really good day and I get all excited and then, like a cruel joke, things go back to normal.”

I suspect there is a definite relationship between CTR and smart pricing, like if you don’t perform when Mr G sends you a quality ad, then the reward drops down to bare cents again.

Therefore there is a lot to be said for the concept of being selective about who you display your ads to!