The Web Hypertext Application Technology Working Group (WHATWG) has sent a Proposal to Adopt HTML5 to the HTML Working Group of the WorldWide Web Consortium (W3C).
HTML5, currently in working draft status is comprised of the Web Apps 1.0 and Web Forms 2.0 specifications. While the W3C XHTML2 Working Group has just been chartered in March 2007, with a goal date for completion of December 2009, the work of WHATWG on the HTML5 recommendation has been ongoing since 2004 and has support from Apple, Opera and Mozilla. In explaining the relationship between XHTML2 and HTML5 the Web Apps 1.0 draft has this to say:
1.3.4. Relationship to XHTML2
This section is non-normative.
XHTML2 [XHTML2] defines a new HTML vocabulary with better features for hyperlinks, multimedia content, annotating document edits, rich metadata, declarative interactive forms, and describing the semantics of human literary works such as poems and scientific papers.
However, it lacks elements to express the semantics of many of the non-document types of content often seen on the Web. For instance, forum sites, auction sites, search engines, online shops, and the like, do not fit the document metaphor well, and are not covered by XHTML2.
This specification aims to extend HTML so that it is also suitable in these contexts.
XHTML2 and this specification use different namespaces and therefore can both be implemented in the same XML processor.
It will be interesting to see if the WHATWG proposal is taken as the HTML Working Group, like the XHTML2 Working Group, was only chartered in March of 2007, and as such, failure to adopt the proposed HTML5 draft would mean the need to reinvent the wheel.