Metadata is described as “all physical data and knowledge-containing information about the business and technical processes, and data, used by a corporation.”  It needs to be modelled, named, collected and stored, just like what IT departments need to do with actual data. This is because metadata itself is also data, and needs planning, or metamodeling.
A metamodel is a model that describes the structure of metadata to be processed and managed. It can be seen as a higher level of abstraction and plans for metadata solutions.
Common characteristics of metadata solutions can be listed as in [105, 76, 95, 27]:
- Standard naming conventions within an organization, or at least through the metadata solution architecture.
- Support for multiple versions of metadata.
- A flexible and extendible metamodel.
- Well-defined repository requirements.
- A common interface to all users for simplicity.
- Multiple and distributed sources; scalability.
- Automated and reusable processes to access to and maintain a metadata repository.
- Update facilities.
- A component-based multi-tier architecture.
- A security management scheme.
In this chapter, we investigate metadata solutions for the Web and Web content. First, we look at XML as a metadata modeling language, and its application areas. Then, we focus on methods used in describing on-line resources, and finally, we identify common characteristics of metadata systems that aim to help generate and manage metadata, and compare several related studies in this field.