WhyDoWork Adsense is a WordPress plugin that allows you to insert Adsense ads on your blog without modifying the template. More then that, you can set it up to show different Adsense ads for articles older then X days (x is the number of days you decide).
For example, you can insert a 468×60 ad at the bottom of a new article, and once that article turns 7 days old it will have a more aggressive 336×280 ad blended with the text from the beginning of that article.
This way your regular readers will not be bothered by your ads, while visitors coming to older posts from search engines or other sources, will see a version that is monetized better.
Another feature is the ability to have articles without ads inserted in them, very useful for payed reviews, where you might not be allowed to have ads (I think it’s the case with PayPerPost).
Installation
Unzip the archive and copy the whydowork_adsense.php file in your wp-content/plugins/ folder. Go to your admin area and activate the plugin and you can find the admin zone for it in the Options area of your blog.
Download WhyDoWork Adsense Plugin from here