1. A method for time-multiplexing the display of a plurality of selected documents, comprising: determining time-multiplexing criteria and space-multiplexing criteria for displaying a plurality of selected documents associated with a concept on a time-multiplexed basis, the time-multiplexing criteria and the space-multiplexing criteria based on at least one of a relevance of each of the selected documents to the concept, a cost per click, or a click through rate associated with each of the selected documents; causing the display of the plurality of selected documents on a webpage at an output device according to the time-multiplexing criteria and the space-multiplexing criteria, wherein the time-multiplexing criteria determines a sequence of the selected documents and a time duration of display for each of the selected documents in the webpage, and wherein the space multiplexing criteria determines a location for display from among a plurality of locations for each of the selected documents in the webpage and a time duration of display for each of the selected documents at the respective locations in the webpage, wherein the causing the display of the plurality of selected documents includes: causing the display of a first document in the webpage for a first time duration determined by either the time-multiplexing or space-multiplexing criteria, wherein the first document is displayed at a first location in the webpage along with content associated with the concept; determining a lapse of the first time duration; causing the display of a second different document replacing the first document in the webpage at the first location based on determining the lapse of the first time duration; determining based on the space-multiplexing or time-multiplexing criteria if the first document should be displayed at a second different location in the webpage; and causing either the display of the first document in the webpage at the second different location or retiring of the first document based on the determining if the first document should be displayed at the second different location in the webpage.