Re:(SDF proposal)

What might the advantage be of using SDF 
rather than, say, XML.

All the arguments put forward for this 
markup system could be made for
XML using an appropriate DTD or
schema.

The additional benefits of XML include
the not insignificant one of being an
adopted 'standard', with mainstream
support.
The steps necessary to gain widespread
support for SDF have been (or are being)
made for XML.

The effort that Steve is proposing might
be well spent in looking towards the 
further adoption of XML in terms of its
accessibility.

regards, DaveP