Distributed Extensibility stays alive and Anne

Anne says "Concerns that HTML5 does not have distributed extensibility. That is, namespaces. What people seem to want is to extend the browser with hundreds of markup languages. (How this keeps things simple to answer was not something I saw addressed.) You need something else than namespaces for that though, to start with. Also, what is wrong with using XML for this?"

My answer is that there is a trade-off between who things are being kept simpler for.  If somebody wants to create a new language that works within HTML - even using XML - and they don't want to wait for it to be approved by the HTML5 WG, then distributed extensibility makes it possible for them.  Yes, if we could do distributed extensibility without namespaces, that would be ideal, but I've yet to see a way to combine separate domains of control with shortnames that doesn't do some form of namespaces, CURIEs, packages, etc. 

I think XML would be ideal for this.  I'd like to see something like Sam's proposal adopted, but the HTML5 WG closed the issue I raised even though it looked roughly like 9 were in favour and 2 against.  I'd even go so far as looking at revising XML the way Anne proposed in XML5 to make it more like HTML if that's what it took to get namespaces and new markup languages into HTML.

While I agree with Sam's assertion that misdirection is going on and IE8 is crucial, I think the real issue is that the anti-distributed extensibility crowd want control over all the languages that could be added into HTML.  There's no changing XML that would make them happy.  I think the goal is that the HTML WG becomes the gatekeeper over any new languages that get added into the browser.  We've seen it with aria-, SVG, MathML.  Note that IE8 has a form of namespaces, and Chris Wilson was a supporter of distributed extensibility on the HTML WG list.