Site targeted Adwords campaigns let advertisers show expanded text and image ads on the sites of their choice. But such advertising camapigns are on a CPM basis, which means you get charged per 1000 ad impressions, irrespective if anyone clicks (what John Chow does) While playing around with Adwords I realized it could turn out to be more expensive than a cost per click startegy as you keep getting charged without any clicks.
Google Adwords announced that starting in March, they plan to begin testing a new site targeting feature called cost-per-click (CPC) bidding. By allowing Adwords advertisers to switch between CPC and CPM campaigns at any time, it will provide more control over budgets and bids.
I think this is a great and much appreciated feature and will provide the flexibility advertisers need for site targeting. They are inviting limited AdWords advertisers located in the US for participating in the CPC site targeting beta – fill the form to participate.