Abstract: A method for selecting network documents as a medium for promotional content. The method comprises capturing a plurality of browsing sessions of a plurality of network users in a communication network, each the browsing session mapping consecutive access to a group of the plurality of network documents by one of the plurality of network users, clustering the plurality of network documents in a plurality of clusters according to the plurality of browsing sessions, selecting at least one of the plurality of clusters as a medium for promotional content, and outputting the at least one selected cluster.