Self-descriptive messages

Hey Darrel. I think I did answer your question, at least by addressing the
most subtle point you raised in the sku message. I hope its clear after
reading my explanation that your last message was not self descriptive
because you used the text/uri-list media type. Also, you'd find that
designing a media type to be able to self-descriptively encapsulate
everything you need to know about a shopping cart in a single URI, is
intractable. It makes for an interesting thought exercise but is
practically unworkable.

P.s. never too late to change the subject line :-)
Mark.