Abstract: A system to pair advertisements with media files is described. A request is processed to find one or more relevant advertisements and determine when to display each relevant advertisement at a temporally contextual point within a video file when the video file is played on a web page. The video file's key concepts and timing information are retrieved from a database. A request is generated for advertisements that contextually match the content in the key conceptual points found in the content of the video file. The timing information is retrieved regarding when the key conceptual points, relevant to returned advertisements that contextually match, chronologically appear in the video file. Contextual relevant advertisements are supplied with temporal information on when the placement of advertisements is most contextually relevant to the content being played in the video file.