My feedback is based on high level review of the specification. I did not study the XML specification throughly. 

 - Generally, I feel that this specification is going in the right direction with respect to enriching and refining the 
semantics of publish/Subscribe paradigm. It also elevates the level of discourse about information value chains. I like 
very much the the separation of the concerns  of an information producer from the concerns of an information consumer as
 well as ensuring that the producer and consumer mutual interests are fulfilled precisely.

- I did not understand why such standard should be limited to the dissamination of information in the Grid environment. 
 I ffeel that the specification have the potential to be applied to a wider scope.
- I would have also liked to see a better definition of the notion of a vacabulary in the specification. I do not think 
that the notion of the vocabulary as being stated in the specification is limited to defining a structure. 
- I suggest that you add an appendix to provide a rationale for the design choices you made in the standard and another 
appendix to provide a blueprint for how the standard can be materialized or utilized in a concrete implementation.