For this to work in general, browsers need a way of rendering arbitrary
MIME content types - the proliferation of these ensures this will remain
a problem until a standard OOP scheme is adopted to allow software re-use.
For this reason the inlined feature needs to be restricted to a very small
number of content types, e.g. XBM, GIF, plain text and HTML.
Including type info in the element is a bad idea - instead it should come
from the object itself.
Perhaps we should have INC just like IMG with ALIGN and SRC, but for plain
text and HTML only (for now).
Dave