1. A system for enabling delivery of at least one advertisement to at least one device over a network, the system comprising: at least one processor having vacancy editor software for enabling a vacancy to be graphically defined; at least one database for storing information related to a plurality of vacancies and information related to advertisements, wherein the information includes attributes; and at least one server for matching at least one attribute of a vacancy with at least one attribute of at least one advertisement; wherein the at least one advertisement to be inserted into the vacancy is selected based on the result of a bidding process and the matching of attributes.