polvo and I were just musing on IRC: rdf newsgroups transmitted over NNTP ... highly distributed, push-model (listener/observer) pattern, can be edited, retracted, expired ... highly scaleable ... MIME friendly ... you can drop or edit an item or insert a new one; it still needs to be able to move one item across to some other cateogory or post to multiple categories...

What's the acronym for an RDF describing a list of RDF feeds? That's what you'd get via XOVER, then use message IDs to pull in unread RDF messages or tune your RDF aggregator to receive the incoming NNTP feed updates.