I've got 2 questions about the interpretation of the HTML5 link relationship "tag".
1. controlled vs uncontrolled vocabularies
The current definition of tag  is "The tag keyword indicates that the tag
that the referenced document represents applies to the current document." Has
there been any discussion within the WG about whether it is appropriate to use
tag for both controlled and uncontrolled vocabularies? The note after that
definition mentions "tag clouds" which are generally for uncontrolled
vocabularies. Would it be worth it to clarify this in the spec?
2. scope of a[@rel='tag']
The definition of tag says it "applies to the current document"...which, to me,
implies the whole document. However, elsewhere in the spec are statements like
the non-normative note in 4.2.4 :
Hyperlinks created with the link element and its rel attribute apply to
the whole page. This contrasts with the rel attribute of a and area
elements, which indicates the type of a link whose context is given by
the link's location within the document.
4.4.4  defines the article element as:
The article element represents a self-contained composition in a
document, page, application, or site and that is, in principle,
independently distributable or reusable, e.g. in syndication. This
could be a forum post, a magazine or newspaper article, a blog entry, a
user-submitted comment, an interactive widget or gadget, or any other
independent item of content.
Would it be worth it to clarify the definition of tag to say that it applies to
the "self-contained composition..." (or something similar) in whose context it
The background for these questions is how WordPress uses (or abuses?) @rel='tag'
and the extension @rel='category' (see [4,5,6]).