Well, we do not speak with one voice, but I can tell you what I mean.
> I ask this for two reasons:
>
> 1. A commonly-offered definition ("data about data") is vacuous in
> actual practice, if not conditioned by further information, since it
> indicates no operational or essential distinction between metadata and any
> other kind of data.
That's true. In our discussion the data is "a schema" and so in my
opinion, the metadata would be "information about the schema." Since I
have urged that we should separate information about types (known
elements, attributes and their semantics) from information about
constraints (how they may be used), I have also urged that we should keep
their metadata separate: "information about types" vs. "information about
constraints."
BTW, XML conflates types (specified in dictionaries) and constraints
(specified in schemas), and the namespaces spec. does also. This causes
much of the confusion and (unnecessary) argumentation about that spec.
> 2. I actually think that there is a valid use of the term "metadata,"
> but I notice that the same word is used in different contexts to mean very
> different things, so I need to know what it means _here_.
I would be glad to hear what you think metadata is.
Paul Prescod - http://itrc.uwaterloo.ca/~papresco
Three things are most perilous: Connectors that corrode
Unproven algorithms, and self-modifying code
http://www.geezjan.org/humor/computers/threes.html