A term specific to smartx, the Demand Marketplace represents the demand side – the buyers– of the supply-demand relationship on the smartx platform. It is the opposite to the Supply Marketplace, which represents all publisher inventory.
Sales houses operate as intermediaries between the Demand Marketplace and the Supply Marketplace. Exceptions are larger publishers (e.g. broadcasters) who sell their own inventory directly to buyers. In this case, the Supply Marketplace and Demand Marketplace are combined as one Multi-Marketplace controlled by the publisher.