The most beautiful overview of what metadata is and does can be found at the Oxford Digital Library website:
Metadata by definition is simply “data about data”, information about the objects stored within our collections, whether these are in traditional or electronic formats. In the standard library world, catalogue records are metadata, as they contain information about the library’s collection of “data”, ie. the books and journals that make up its collections. Metadata records in the traditional library fulfil several functions, including allowing users to find items, allowing them to assess their usefulness, and to allow librarians to administer them correctly. The same principles apply to objects within the digital library.
Metadata can take several forms, some of which will be visible to the user of a digital library system, while others operate behind the scenes. The Digital Library Foundation (DLF), a coalition of 15 major research libraries in the USA, defines three types of metadata which can apply to objects in a digital library:-
- descriptive metadata: information describing the intellectual content of the object, such as MARC cataloguing records, finding aids or similar schemes
- administrative metadata: information necessary to allow a repository to manage the object: this can include information on how it was scanned, its storage format etc (often called technical metadata), copyright and licensing information, and information necessary for the long-term preservation of the digital objects (preservation metadata)
- structural metadata: information that ties each object to others to make up logical units (for example, information that relates individual images of pages from a book to the others that make up the book itself)
In general, only descriptive metadata is visible to the users of a system, who search and browse it to find and assess the value of items in the collection. Administrative metadata is usually only used by those who maintain the collection, and structural metadata is generally used by the interface which compiles individual digital objects into more meaningful units (such a journal volumes) for the user.
Lovely. There’s a fairly simple synopsis of the different standards on the same page (seeing MARC get a mention still sends chills down my spine) and I’m very happy that, as a non-librarian, I don’t have to use any of them. A recommended resource.