extensibility example

[Bruce D'Arcus <bruce.darcus@OpenDocument.us>]

I also want to quickly highlight another point in the example archive, 
and that is the requirement for extension.

Here's the example fragment, where I understand the dc, dcq, and vcard 
namespaced stuff as default modules, and the foo as totally arbitrary 
(in the sense that you will not find the "foo" namespace in the 
schemas).

       </v:VCard>
     </b:author>
     <!-- use dc:type for typing, with controlled URI list -->
     <dc:type rdf:resource="http://purl.org/net/biblio#Article"/>
     <dc:title>Some Title</dc:title>
     <!-- arbitrary "simple extension content -->
     <foo:simple>X, Y, X</foo:simple>
     <!-- arbitrary "rich" extension content -->
     <foo:annotation>
       <foo:Note>
         <dc:creator>Jane Smith</dc:creator>
         <foo:content>Some random notes.</foo:content>
       </foo:Note>
     </foo:annotation>
     <dcq:isPartOf>

This is the sort of practical extension needs that I could foresee for 
different bibliographic solutions.

Worth noting that it's modeled in a way that is simply a tighter 
definition of the current extension rules in ODF metadata ("foreign 
namespaced content is allowed", or something like that).

Bruce