WikiEducator roadmap/Support WYSIWYG semantic editing
Semantic MediaWiki is an example of a powerful extension for MediaWiki that adds support for arbitrary metadata to articles, which can be exported in the standard RDF format. Articles can have attributes and links can have relation types, resulting in machine-readable information about the semantics of a wiki. SMW supports a simple query language so that various questions can be asked of the stored data: "Sort all upcoming events by data", "Give me a list of countries by GDP", and so on.
SMW does make the existing MediaWiki editing syntax more difficult to learn. Semantic annotation functionality, in the long run, must be as easy to use as the italics button in a word processor. The combination of reliable WYSIWYG support for MediaWiki with such semantic capabilities could make for an interesting and valuable project.