“Stuff” about “Stuff” — the differing meanings of “metadata”

Metadata is a complex subject, and many of its complexities are extremely subtle. To further complicate matters, “metadata” has become an overloaded term, and is often used in different contexts by different communities with different motivations. It is very easy to overlook this diversity of motivation since these communities share many of their tools and problems. This paper identifies three different such “schools” of metadata and discusses their history and motivations.