More Information: http://wpplugins.com/plugin/861/search-engine-visitor-ads/
This plugin recognize visits from search engines and applies special adverts for this kind of visitors.
You can automatically insert Ads (Google AdSense, Contaxe…) above and below the posts and in the footer.
You have also the possibility to insert the ads with the help of Snippets direct in the theme.
Search Engine Visitor Ads works also with caching plugins like WP Super Cache, Hyper Cache and W3 Total Cache.