Abstract: A system and method capable of reading machine-readable labels from physical objects, reading coordinate labels of geographical locations, reading timestamp labels from an internal clock, accepting digital text string labels as input obtained directly from a keyboard type input device, or indirectly using a speech-to-text engine, and treating these different labels uniformly as object identifiers for performing various indexing operations such as content authoring, playback, annotation and feedback. The system further allows for the aggregating of object identifiers and their associated content into a single addressable unit called a tour. The system can function in an authoring and a playback mode. The authoring mode permits new audio/text/graphics/video messages to be recorded and bound to an object identifier. The playback mode triggers playback of the recorded messages when the object identifier accessed.