Optimization constraints are used to select an appropriate content item from an available group of content items which are ordered in a specific manner to facilitate the proper selection of the content item, even if the exact item desired is not present. The server is then able to insert the selected content item into the outgoing content page requested by the client. The optimization constraints can be, but are not limited to, anyone of the following: communication channel performance (bandwidth), client operating system, client processor, client display capabilities, client installed software (video or audio codecs for example), and/or user preferences. A software product and method enable selective delivery of content to client devices of varying performance characteristics, including varying bandwidth, by selective filtering and inclusion of markup language content using tags demarcating optional content. An optimization constraint is used to select one of the items.