Confused about CPC and CPM.... Here you go...

Goole has two types of advertisement - cpc and cpm.

What is CPC??
CPC means cost per click. If your site is displaying this type of adds you will get paid per click. Most of the adds are CPC.

What is CPM??
CPM means cost per 1000 impressions. It pays per 1000 impressions. CPM has been recently introduced. Whenever the page on which you have adds loads one time it counts it as one impression. It will pay you whenever you reach 1000 page impressions.

Most of the ads you will see on your site are pay per click ones. The other type has been recently introduced and tend to be image ads in the main.

Google adsense is smart enough to decide what adds are performing better on your website. To get CPM adds on your site, cpm ads have to outbid the regular pay per click ones, and not that many advertisers want to pay that much on cpm campaigns.