From Diplomatic Standards

Semantic MediaWiki (SMW) is an extension of MediaWiki – the wiki application best known for powering Wikipedia – that helps to search, organise, tag, browse, evaluate, and share the wiki's content. This wiki has SMW installed.

The actual homepage of Semantic MediaWiki, including user documentation in multiple languages, is semantic-mediawiki.org. The homepage is the most up-to-date source of information if you need help in using Semantic Wiki.