AdSense Adjustments Reap Earnings Increase
Google AdSense optimization tips for blogs and adsense placement suggestions that vary based on the type of traffic sources to your blog.
Losing AdSense Revenue from All in One AdSense and YPN
There is an old article about losing revenue from the All in One AdSense and YPN plug-in for Wordpress but you can make sure you won't lose any earnings.
Kontera vs AdSense
I ran Kontera and AdSense on my blog for 7 days to compare which earned more income, AdSense won by a wide margin on all of my blogs except one.