1. A policy based content delivery system comprising: a mobile device configured to select and receive content; a content source configured to provide content selected by the mobile device to a content server, the content source further configured to modify content selected by the mobile device prior to the content server providing the selected content to the mobile device; and a content server configured to discover content at a content source and provide a list of detected content to the mobile device for selection, the content server further configured to instruct the content source to provide the content in accordance with a policy, the content server including a policy enforcement engine configured to implement a policy.