Lotsa FUD introduced by the Semantic Web initiative, KM hype etc. But which are the practical ones in terms of document management?

3 come to mind: hierarchical classification of docs, a thesaurus where terms are defined and relationships between documents (and people).

Hierarchical classification: basically the Windows Explorer model where documents are placed into folders. A variant of this is faceted classification. A faceted classification system is one in which each document is classified according to several separate hierarchical classification systems, called facets.

Thesaurus: describe synonyms, preferred/obsolete terms, broader/narrower term relationship. A thesaurus defines a convention when describing document metadata. Its in my opinion that its too ambitious (hence unpractical) to apply the thesarus to document contents as well.

Relationships: many names for this, like document collections, related documents, etc. A relationships consists of: players, the roles played by the players, and the relationships between the roles/players. This can be a binary or an n-ary association.

Did I miss anything out?