RDF support for anonymous users in Drupal

Hi,

I've left out the support for anonymous users support in the initial patch
which was committed to Drupal core as I wanted to think about it a little
bit more. Time helps to come up with better ideas (I hope!), but we should
not wait too much longer. I'm just about to propose a patch to add support
for exporting RDFa for anonymous users but I'd like to make sure we get this
right as this will be set in stone after Drupal 7 is released.

See some example:
- Registered user comment:
http://drupalrdf.openspring.net/comment/1#comment-1
- Anonymous user comment:
http://drupalrdf.openspring.net/comment/7#comment-7

In the case of a non registered user leaving a comment, Drupal offers to
leave her name, homepage and email address (though the email address is not
displayed for privacy reasons). The default markup is:

<a href="http://openspring.net/" rel="nofollow" class="username">Stephane
Corlosquet (not verified)</a>

We don't have a user profile URI here, but a homepage URL only. From the
initial feedback I got earlier, it seems we could create a blank node of
type foaf:Agent or sioc:User and use foaf:page to link it to the homepage. I
suggest the following markup:

<span rel="sioc:has_creator">
  <a typeof="sioc:User" rel="foaf:page nofollow" href="
http://openspring.net/">Stephane Corlosquet (not verified)</a>
</span>


To keep things simple, I'm very tempted to reuse the sioc:User mapping we
already have for the regular registered user. Is it ok not to use a
foaf:Agent or foaf:Person in this case, and link a sioc:User to a homepage
with foaf:page?

Steph.