What is CPC bidding for placement targeting?

Google has introduced a new feature for AdWords advertisers: CPC bidding for placement targeting. It allows you to make cost-per-click (CPC) bids when you create placement-targeted campaigns in your AdWords account. (Placement targeting was formerly called site targeting.)

Until now, placement-targeted campaigns were available only with cost-per-thousand-impressions (CPM) pricing. Now when you create a new placement-targeted campaign, you can choose to price the ads using either CPC or CPM. If you choose CPC bidding for your placement-targeted ad, your account will be charged each time a user clicks on your ad. You won't be charged for each impression. If you choose CPM bidding, the reverse is true: you'll be charged for each impression, but not for clicks.

Other features of placement targeting remain the same, however you bid. Your ads will appear only on the sites you target. Your ads will continue to compete with other placement-targeted and keyword-targeted ads in the Google Network. You can use either CPM or CPC pricing with text ads, image ads, and video ads in placement-targeted campaigns

source: CPC Bidding