Microformats Hop on Semantic Web 'Griddle'

There are a lot of different ways to connect the dots of content and data that comprise the Web. Two of them are microformats (define) and the GRDDL (Gleaning Resource Descriptions from Dialects of Languages) Semantic Web construct.
Both approaches have attempted to make sense of content by making use of metadata descriptors, but they differ somewhat. The World Wide Web Consortium (W3C) is trying to change that.
"Microformats and the Semantic Web always had a lot in common at a high level, but GRDDL fills in a few technical details so that they interoperate at a practical, running-code level," Dan Connolly, the W3C GRDDL Working Group staff contact, told InternetNews.com.
While microformats use XHTML and HTML, GRDDL (pronounced "griddle") extracts RDF (define) (Resource Description Framework) data from XML so that it can be transformed or understood by other applications in a mashup or other application settings.
The way that GRDDL will work with microformats will require some effort from microformat authors.
"Microformat authors that want their data to integrate seamlessly with other semantic Web data should use well-formed XHTML and profile URIs," Connolly explained. "For example, the dbpedia project takes millions of facts from Wikipedia and exports them using URIs and RDF and SPARQL."
Connolly explained that the HTML specification lets authors use any name they like for conventions for class, as well as rel attribute values for styling and other processing. The conventional microformat names are hcard, hcalendar, summary and description, among others.
HTML has a special "profile" hook to use a URI to take those document-local conventions and share them in the Web. Some microformat documents use the profile hook, but not all do.
GRDDL links the profile documents to XSLT (define) transformations that allow machines to exploit microformats and other syntax conventions.