1. A engine for use with a display, comprising: a presenter that presents at least two audio/visual works; at least one software application capable of at least one metadata-related interaction with the at least two audio/visual works; communication points over which the audio/visual works are received, and over which at least a portion of the at least one metadata-related interaction occurs; a hierarchical taxonomy that effects a common metadata reference to each recurrence of a particular object across the audio/visual works, and across each of the at least one metadata related interaction.