The site targeting program allows marketers to select which sites within Google's network will display their ads. Google said it's expanding to include cost-per-click ads in an attempt to provide more flexibility. "CPC bidding has often been requested by advertisers who would like to utilize site targeting, but are not comfortable bidding on a CPM basis," Google announced this week on the AdWords blog.

The company also put out a call on its blog for marketers who wish to participate in a test of the new feature.

The move is expected to make site targeting more useful to advertisers who have aim for both branding and direct response with their campaigns, said David Berkowitz, director of strategic planning for 360i. "Even brand marketers often have direct marketing and traffic goals, and they'll want to use CPC pricing for those campaigns," he said.

Google started the site targeting program in June 2005, in an attempt to broaden its appeal to brand marketers.

This news story is important. I recommend that everyone read it.