*Steven Pemberton*, 2006-08-30:
> We have often had such requests for datatype elements, and one of  
> the questions was always "where do you stop?".

I don't know, but it seems the HTML WG stopped too early and headed  
into another direction.

> 	<span datatype="xsd:date" content="2006-08-31">tomorrow</span>

Maybe it's just me, but I like the solutions of WHATWG and  
Microformats.org better, despite or maybe because their use of much  
less fancy techniques.

<http://whatwg.org/specs/web-apps/current-work/#the-t >:

	<t datetime="2006-08-31">tomorrow</t>

<http://microformats.org/wiki/datetime-design-pattern >:

	<abbr class="dtstart" title="2006-08-31">tomorrow</abbr>