Payment method where the client pay on a "per referral" basis. The referrals in this case are being generated from search engines, where the client pays for unique traffic generated to their web site from their search engine campaign. Click here for further information of CPC campaigns.
The price paid by an advertiser to a content site. When buying on a Cost Per Click model, the advertiser and content site have mutually agreed that the content site will continue to display the advertiser's ad creative until X number of clicks have been delivered - the amount purchased. As with other forms of online advertising, is dependent on content, audience reached and targeted delivery - Untargeted being lower priced, targeted to an affluent audience being at the high end of the rate scale.