Metadata
Types of metadata formats
1 relatively unstructured data automatically extracted from resources and indexed for use by robot-based Web services
2 structured formats simple enough to be created by non-specialist users. Usually manually created, but some data may be extracted automatically.
Examples: ROADS, Dublin Core
3 specialised formats, developed to organise complex relations between objects or collections of objects and are often based on implementations of SGML
Examples: TEI header, MARC