A video hosting service stores and provides video content to a client via a network. Advertisers search for videos to target by entering search criteria into a user interface. Advertisers can search based on characteristics of the audience (viewers) of the videos, such as age range, gender, and interests of the viewers, and/or based on metadata associated with the videos. A set of videos that meet the search criteria is then retrieved. Advertisers can select individual ones of these videos or groups of these videos. The selected videos or groups of videos can be added to a media plan. The items from the media plan can be imported into an advertising campaign management system, wherein the advertiser's ads are associated with the selected videos. Subsequently, viewers who view the selected videos also view the advertiser's ads in connection with the videos.