actually, the dispatching is not implied by the content-type -
the recipient agent is free to dispatch each content as it sees fit.
the content-type really is just labelling the data representation
used by the content.
Labelling is definitely the intent, but that has always been filtered by a
desire to use the label as a basis for various sorts of actions. So yes,
dispatching isn't implied, but the labels are constructed to facilitate
dispatching. This has had mixed results -- the primary type concept, for
example, has worked well in some cases and poorly in others.
Additionally, we have been reluctant to go much beyond labelling the
representation of the data in the content type field. Information about
whether an image is black and white or color, what Postscript features
are employed, and so on belong somewhere else. We didn't address where that
was in the original MIME work, but the content-features work has done this.
Ned