The W3C GRDDL Working Group has posted the last call working draft of Gleaning Resource Descriptions from Dialects of Languages (GRDDL). According to the abstract,
GRDDL is a mechanism for Gleaning Resource Descriptions from Dialects of Languages. This GRDDL specification introduces markup for declaring that an XML document includes gleanable data and for linking to an algorithm, typically represented in XSLT, for gleaning the resource descriptions from the document.
The markup includes a namespace-qualified attribute for use in general-purpose XML documents and a profile-qualified link relationship for use in valid XHTML documents. The GRDDL mechanism also allows an XML namespace document (or XHTML profile document) to declare that every document associated with that namespace (or profile) includes gleanable data and for linking to an algorithm for gleaning the data.
The result of such a glean is an RDF description of the document.