Generally display ads are served on a CPM (cost per thousand impressions) basis or a pay-per-click basis. Often publishers, like Facebook for example, allow an advertiser to choose which method they would prefer to use. Generally the trick with CPM advertising is to get the highest CTR possible because you are paying for the impressions whether the ad is clicked or not. Say the CPM rate is $10/100 if your CTR is 1% your cost per click is $1.00. raising the ctr to 2% would give a $.50 cpc. Raising CTR directly effects your bottom line. Not to mention it drives more traffic to your landing pages.
Perhaps you would rather tune your creative to qualify visitors vs drive volumes of traffic. Than CPC may be a better option. This technique not only requires proper placement but, to deliver the message effectively and qualify visitors to discourage unqualified clicks, takes strategic creative.
Our display ad team can develop a strategy which is right for you and execute it with creative element, fine-tuned to achieve results.