> The best way to use transclusion for
> reuse, though, is with entities.  If something's part of your
> document, make it so.  Since a system identifier in XML is a URI, and
> a URI can include a fragment, and that fragment can be an XPointer,
> there's really no limitation on what an entity can be.
Au contraire, h=E9las!  XML spec section 5.2:
# The SystemLiteral [specified for an external entity] is called the
# entity's system identifier. It is a URI, which may be used to retrieve
# the entity. Note that the hash mark (#) and fragment identifier
# frequently used with URIs are not, formally, part of the URI itself;
# an XML processor may signal an error if a fragment identifier is given
# as part of a system identifier.
"May", of course, is not synonymous with "must", but one cannot count
on reliable transclusion of document parts in this way.  XLink
does allow it.
> The reason Steve and I proposed always
> distinguishing transclusion is that otherwise, there will be too much
> fear of intellectual property theft, and the Web could stagnate.
> Theft is always a possibility (copy and paste always works), but it
> shouldn't be made easy.
An essential part of Xanadu, which the WWW does not have, was a chargebac=
k
mechanism, whereby the original author of a transcluded document is
paid pro rata when someone buys the right to read the transcluding
document.
This is related to the "mechanical licensing" policy for sound
recordings: one may always, on payment of compensation, play someone
else's copyrighted sound recording even without permission.
A variety of clearinghouses are used to implement this policy.
-- =
John Cowan	http://www.ccil.org/~cowan		cowan@ccil.org
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)