A management system brokers, between a seller and a buyer, at least a portion of the seller's inventory of advertisement impressions that the seller can render within a web page of internet traffic. The management system comprises a traffic block definition tool adapted to define traffic block parameters for at least two discrete traffic blocks of the advertisement placement. The traffic block parameters for each discrete traffic block comprise a volume parameter and a duration parameter. A sales management tool is adapted to associate advertisement content and a buyer compensation parameter to each salable event. An order fulfillment system: i) directs placement of highest yielding advertisement content if, for each discrete traffic block, a delivered volume of sales events is higher than its minimum fulfillment threshold; and ii) if, for any discrete traffic block, delivered volume of saleable events lower than its minimum fulfillment threshold, directs placement of the advertisement content associated with that discrete traffic block.