PlatypusWiki is an ongoing project that started on 23 December 2003. It is an enhanced wiki with ideas taken from SemanticWeb. They have called it a Wiki:SemanticWikiWikiWeb. It offers a simple user interface to create a wiki page plus metadata according with W3C standards. It uses ResourceDescriptionFramework (RDF), RDF Schema, and OWL (Web Ontology Language) to create ontologies and manage metadata.
A temporary demo is available at: http://platypuswiki.sourceforge.net/demo/, your help and feedback are wellcome. -- PaoloCastagna?
See also RdfForWikis.
Other interesting features: