Review of Distributed Extensibility in HTML5

I propose the following as a starting point for the TAG to offer to the
HTML WG.
 
Dear HTML WG,
 
The TAG has reviewed the proposal in
http://intertwingly.net/blog/2007/08/02/HTML5-and-Distributed-Extensibil
ity.  In short, we believe it is a very interesting start of a proposal
for stronger support for distributed extensibility on the web in the
HTML language.  We hope that the Working Group will give it and it's
natural subsequent refinements or similar alternatives very serious
consideration.  
 
The core design principles that are embodied in it and that we support
are:
1. Allowing distributed extensibility using xml namespace like syntax.
2. Robustness in handling unknown markup.
3. Re-use of existing syntax and idioms for extensibility
4. A balance between simplicity of authoring and richness of
functionality.  
 
On the important issue of default prefixes, many TAG members have
expressed concern about various usages of some attributes and attribute
values, but we have no opinion to offer at this time.
 
Cheers,
Dave