You can refer to the recent Adsense official blog post on finding the source of your reduced earnings at: http://adsense.blogspot.com/2008/03/diagnosing-and-treating-revenue.html http://adsense.blogspot.com/2008/03/diagnosing-and-treating-revenue_06.html Now, back to your question.. you should study have your search engine traffic reduced? The initial traffic may be curious and click on your ads but as time goes by, regular visitors tend to not click on the ads but only visit to read your post.. Therefore, these traffic will still add up to your traffic count.