incrediBILL - 8:32 pm on Jan 13, 2011 (gmt 0)
There is no reason to be condescending to their interpretation of events. eCPM can defy logic sometimes.
There's also no reason to think Google is "out to get you" for everything that happens.
Google is primarily run on algorithms, with some minor human intervention, and when things go south you have to look at what caused it to go south.
Just because your traffic looks similar doesn't mean you're bringing in the right traffic.
Just because your ads look similar doesn't mean they pay the same.
Lots of things change, including the algorithm that smart prices your site, so one day you meet a certain quality level and a switch is flipped and the next day you don't.
Happens in AdWords all the time too.
Basically, if your site can't be adapted to meet these changes, it won't survive on the web, let alone pay well in AdSense.