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How To Edit
Metadata is structured data about data. Metadata usually describes some object or resource with the aim of improving a machine's understanding of it.
A number of different metadata proposals and standards have arisen, which reflect ongoing research in this area and the various and diverse applications of metadata.
Attribute based metadata standards provide a method of assigning attributes (or properties) to a resource.
Attribute-based metadata allows simple statements to be made about resources. Object-based metadata provides more flexibility.
Where is Metadata stored?
Metadata is usually associated with a resource using one of two methods:
- Distributed: metadata is stored alongside the resource it describes. Metadata standards such as HtmlMetaTags may even require the metadata to be embedded within the resource.
- Advantage: Each resource (and its metadata) is a self-contained unit.
- Disadvantage: Increased maintenance overheads - metadata has to be collected from many locations, and any changes to the representation must be made to all effected metadata.
- Centralised: metadata is stored separatly from the resource it describes, in a central repository.
- A central repository offers greater maintainability than a distributed approach.
- Easier for search engines and indexers to process the metadata - all in one place.
- All metadata represented using same standard.
- If repository is overlooked by search engines and indexers, large loss.
- In an environment with a large collection of unrelated metadata authored by many users, the successful integration of diverse users and metadata representations into a single repository is likely to fail. A community-driven distributed approach may be more practical.
- W3C Metadata Activity  (now superceded by the W3C Semantic Web Activity )