Metadata is data about data
Where you have content, including grapics, illustrations, flash movies, text, you can also have descriptions of attributes of that content. This page has content, of which this paragraph is one part. The metadata for this content includes its page title (“MetaData“), the date of last modification, the size of the page, the category the content is classified into, etc.
Metadata falls into five categories: administrative, descriptive, prescriptive, technical and use. It is descriptive metadata that we most often use in controlled vocabulary creation efforts. So once the descriptive metadata is harvested through indexing efforts, the classification can begin.
For non-metadata-ites here are some notes TomWorthington? did for e-commerce students at The Australian National University:
- [Metadata for E-commerce]
- [Case Study: Metadata Management Facility And Search Tool for New Zealand]
- [Electronic Document Management and the Digital Library for E-commerce]
- [JoDI Volume 2 Issue 2]
- [Editorial: Introduction to a Special Issue on Metadata: Selected papers from the Dublin Core 2001 Conference]
- [RDF Declarative Description (RDD): A Language for Metadata]
- [zetoc: a Dublin Core Based Current Awareness Service]
- [Terms Does Your Metadata Use? Application Profiles as Machine-Understandable Narratives]
- [Author-generated Dublin Core Metadata for Web Resources: A Baseline Study in an Organization]
- [A Metadata Kernel for Electronic Permanence]
- [The ABC Ontology and Model]
- [Multilingual Access to Dublin Core Metadata of ULIS Library]
The UK Government’s Office of the e-Envoy has released their e-GovernmentMetadata? Set for comment:
This metadata set, based closely upon the Dublin Core, is intended to meet the needs of e-Government in the UK, but is already attracting significant interest overseas.
It mentions AGLS (Australian Government Locator Service), but is more akin to the Recordkeeping Metadata Standard for Commonwealth Agencies (RKMS?). RKMS? extends AGLSfor record keeping purposes with items such as “Disposal” (also in the UK standard):
- [Meta Data Repositories: Where We’ve Been and Where We’re Going]
- A review of the history of meta data repositories helps to understand their role and highlights the need for companies to manage corporate knowledge.
- [E-Government Metadata Standard], 
- [E-Government Interoperability Framework]
- [pan-government thesaurus]
http://bitzi.com/about/intro – a kind of distributed metatagging effort for all types of files – seems focussed on adding metadata to P2P filesharing.
“Labels are the words and phrases throughout your site that identify content. Employing a labeling scheme and applying effective, coherent labels can make the difference between a site that’s a pleasure to navigate and one that doesn’t get bookmarked because it’s too much trouble to use. “