see also 
http://lists.w3.org/Archives/Public/www-archive/2009Jan/0002.html

http://lists.w3.org/Archives/Public/public-powderwg/2009Jan/0021.html


how to make this work?

rapper --trace -i grddl powder.xml 
rapper: Parsing URI file:///Users/danbri/working/foaftown/2009/powder/powder.xml with parser grddl
rapper: Serializing with serializer ntriples
rapper: Processing URI http://www.w3.org/2007/05/powder/
rapper: Parsing returned 0 triples