All computers can do is play with symbols: labels and pointers.
XML is just a syntax for annotating strings with labels and pointers. It
may even be that successful systems try to defer or avoid or hide issues
of semantics as much as possible: some data with a highly specific
semantic is just sent as a string, or as a number. Rather than saying
"how can we clarify the semantics of this data" sometimes you need to
say "how can we neutralize the semantic problems with this data?"
Cheers
Rick Jelliffe