adaptive blue has released a header/meta tag scheme
to simplify semantic tagging of content items -

http://www.readwriteweb.com/archives/wine_film_and_books_adaptive_b.php

"Semantic web company Adaptive Blue has published what it hopes
will become a standard for publishers who want to signal in their
header tags when a webpage is primarily about a particular book,
film, wine or other type of objects. From search to trend analysis
to a richer browsing experience - the developments that could come
from adoption such a standard are many.

"Called AB Meta, the format was developed in concert with a number
of other web companies and is aimed to be part of a larger effort
to pick up where existing Semantic Web and microformats markup
leaves off. It's simple and extensible.
...

"Bloggers who want to mark up particular pages or post pages with
AB Meta can do so using Dougal Campbell's HeadMeta WordPress
plugin. Some post-level meta data editing is possible with Typepad
but Blogger users are out of luck. Hopefully someone will build a
UI for self-publishers.

"For commercial publishers and retail sites, the AB Meta standard
should be much easier to implement across their sites. In addition
to the new spec drawn up to describe objects, AB Meta also
leverages existing Dublin Core markup when available."