Just like every other dublin core element, dc:valid is very good for labeling things, and very bad in a wire format. In fact, I've even read emails from OCLC folks claiming that the few restrictions RSS1 "modules" make don't apply when using them in Atom or RSS2. So, I don't really see how it could be a "best practice". Shame on Media RSS.
I support draft-snell-atompub-feed-expires-04.txt moving to Proposed Standard. (FYI-- silence does not mean consent during a last call. Movement onto the standards track requires on-the-record comments supporting the draft... AFAIK). Robert Sayre
