My cost per click has been going down over the past coupla months - dunno why and Adsense staff are not telling me exactly why. 'Smart pricing' has been brought up. Me personally, I don't really want to get into details how they figure my share of pay per click - I just want it to be higher. So, I was thinking of writing a script that regularly logs into my adsense account, calculates average cost per click for that day, and based on that figure decides how much adsense to serve. So when the average price per click drops below certain value, I could take out a portion (up to 90%) of the ads. When/if it comes back up, I start serving more ads again. My reasoning is this - I can afford to loose a coupla hundred bucks on Adsense and to experiment with it, but I don't want my visitors to leave my sites too early...unless I get paid for it You think it'd be worth a shot?
before I start making any suggestions (not even conclusions) it will be a few weeks, since smart pricing which seems to determine our payouts is not reacting immediately, but I will post if I find out something interesting.
Maybe you want to direct to a more high paying keyword, and work from there to keep from getting into this dilemma, I am not saying change your site altogether, but maybe looking for something a bit better.