For Schema.org, the accessible metadata would be properties that can be applied to the CreativeWork type or subtype. We are particularly interested in using it them to enhance LRMI proposed schemas to enable use cases such as, "I am a teacher for the deaf and want to find captioned videos that help a deaf student achieve proficiency in common core standard X."
General Information about Schema.org:
Rich Snippets and Schema.org
- Google has a quick overview of rich snippets withe a few examples at http://support.google.com/webmasters/bin/answer.py?hl=en&answer=99170. There is a higher-level link on rich snippets that gives more context that is useful as well.
- Schema.org and the list of current types adopted http://schema.org/docs/schemas.html and a tutorial at http://schema.org/docs/gs.html
HTML Microdata at the W3C and beyond
- The last working draft is http://www.w3.org/TR/2012/WD-microdata-20120329/ and the current document in progress (editor's draft) is http://www.w3.org/html/wg/drafts/microdata/master/
- I found this resource http://diveintohtml5.info/extensibility.html useful on microdata
- and http://www.entrepreneur.com/article/223074 gives the overall case for the use of microdata