Most Google Adsense publishers are not aware that Adsense has a Premium Publisher Program for the elite few — called such because not all websites can apply or be invited to the program.
The Premium Publisher Program is exclusive to websites that receive more than 5 million search queries or 20 million page views per month. When a site hits that mark, Google normally sends an invitation to the site to become a Premium Publisher.
What do Premium Publishers get? Apparently, a lot of the good stuff not available to “normal” Adsense publishers.
Take a look at how Google pampers their Premium Publishers.