netmeg - 7:06 pm on Mar 30, 2013 (gmt 0)
Back in 2009, my click count was as high as 16x to what it is today. Why the massive drop? I attribute it mostly to a perfect storm of AdSense and Google changes.
Don't rule out ad blindness/fatigue. People see more ads in more places every year, and they probably ignore them more every year too.