Semantic Schemas extension
by Ankit Garg for Wikimedia Foundation
Short summary: Semantic Schemas a proposed extension , that would let users and admins define everything about the wiki's data structure via XML contained within wiki pages. That XML in turn would be used to generate all the other relevant pages: templates, properties, forms, etc. And the XML would be editable via a helper form, so that ideally users would never have to do direct XML editing. Also, the XML could theoretically be imported from, and exported to, other data-structure formats.