1. A method for obtaining metadata associated with a media program, the method comprising: receiving, by a computing device, a media program callback message to request the media program at a content delivery system from a client device displaying a webpage retrieved from a host server, wherein: the media program is embedded in the retrieved webpage, the callback message is generated by the client device executing coded instructions in a source code for the webpage, and a callback address to the webpage is included in the callback message by virtue of the callback message being generated; determining, by the computing device, the callback address from the callback message; and storing, by the computing device, the callback address as metadata associated with the media program in the database in response to determining the callback address, wherein the metadata indicates the media program is embedded in the webpage identified by the callback address.