Content or Metadata?

David Megginson david at
Thu Dec 2 19:52:05 GMT 1999

Tim Bray writes:
 > At 01:14 PM 12/2/99 -0500, David Megginson wrote:
 > >The second example is an interesting choice.  After all, the full OED
 > >would probably count as metadata to people who bother to make the
 > >distinction: 
 > These are murky waters.  But there are a couple of things that are
 > incontrovertably true:
 > 1. All metadata is data.  Given an aggregation of data items, each 
 >    application can and will make its own decisions as to which is "data"
 >    and which "meta".  Thus a common syntax for both, to the extent
 >    possible, is a good thing.
 > 2. Not all data is metadata.  Examples: this email message; Chopin's
 >    Nocturnes; Tuxedo.gif.  

Hmm -- see below.

 > Operationally, my experience suggests that in stuff that is
 > not metadata, ordering matters.  The converse is true; if ordering matters, 
 > it's probably not metadata.   There are exceptions but you have to
 > work pretty hard. -Tim

How about ranked search results, or the top ten Web sites?  I didn't
really have to work that hard -- that's why RDF has the horrible
kludge where the rdf:li property automatically changes into rdf:_1,
rdf:_2, etc.

Here's a trickier example: is a film review metadata or data?  It's
prose and it's ordered, but I'm reading it only because I'm interested
in something else.  I could even extend that to a picture of a tuxedo
and beyond, but I'll spare the readers for now.

The point is that the content/metadata distinction is not a property
of the data but a property of how the data's actual use.  If I use
something for its own sake, it's content; if I use something for
something else's sake, it's metadata.

Tim is right that Chopin's Noctures are much more likely to be used
for their own sake in most familiar contexts, but consider a
collection of metadata about influences behind a musical piece: even
there, there is no crisp line.

All the best,


David Megginson                 david at

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