1. In a computer-based editing system for editing a time-based media program, a method comprising: receiving an instruction to associate metadata with a selected portion of the program; determining a type of the metadata, wherein the type of the metadata is one of a predetermined set of metadata types; identifying a software component available to the editing system that is configured to process metadata of the determined type; and associating the metadata with the selected portion of the program by executing the identified software component to process the metadata.