Response to Guidelines for new URI Schemes

This is a response to "Guidelines for new URL Schemes,
draft-ietf-urlreg-guide-05.txt, by Masinter, Alvestrand, Zigmond, Petke

Summary:  Good overall, but I have two general recommendations,
described in more detail below. 

  1. Change "locator" to "identifier" throughout.
  2. Separate identification from protocol throughout.

Section "Syntactic compatibility"

Regarding the sentence starting "If a URI scheme that has embedded links
in content accessed by that scheme does not share syntax with a
different scheme," do we agree that "accessed by that scheme" is
shorthand for "accessed by a protocol associated with that scheme"?  I
have more comments on protocol relationships below.

Regarding the general caution that "new schemes must have demonstrable
utility and operability", it is fine to consider what might happen if a
new scheme is deployed.  But there is another concern that would appear
to make this caution is almost irrelevant since very few if any new
schemes will likely be deployed for use by global identifiers.  The main
reason is the catch 22 that providers are very unlikely to use a new
scheme in documents if few clients support it, and producers of client
software are unlikely to support a new scheme unless there are providers
that use them to make the extra code worth while.

On the other hand, this extreme difficulty of deployment would make it
all the more important that any new scheme that does get deployed follow
the compatibility guidelines.  And furthermore, use of relative URIs