Enlighten People:     

Google has not yet crawled all the pages of your website.
Your page may contain sensitive content for which relevant paying ads will not be displayed.
Your website is using session IDs in the URL.
The AdSense code was placed within an IFRAME.
Your web pages are behind a login.
There are too many URLs added to your account filter list.
Your web page may not contain enough content.
Your site content is primarily in an unsupported language.

Your site has restricted access using a robots.txt exclusion. If you would like to grant Google's crawler access your pages, you can do so without granting permission to any other bots. Simply add the following two lines to the top of your robots.txt file:

User-agent: Mediapartners-Google*
Disallow:

Your website is using frames. In order for Google to serve better targeted ads to the content on your website, select the Framed page checkbox from the Ad layout code page when generating your ad code.

Labels: adsense, optimization