Abstract: Embodiments consistent with the present invention enable an advertising client to vary terms of an advertising campaign automatically in order to react to changing business conditions. An advertising client and a publisher establish terms of an advertising campaign including a unit cost for placement of advertisements and a range of acceptable changes. The unit cost may use any pricing model, such as cost per mille, cost per click, or cost per action. During the advertising campaign, the advertising client may submit a change that is automatically implemented to alter the advertising campaign.