According to W3C News Archive, XHTML 2 working group is expected to stop work end of 2009 and W3C is planning to increase resources on HTML 5 instead.
The magazine says that the list was going to change in the future with the development of HTML 5, but it was expected to remain for many years.
You can download the cheat sheet here.
Meanwhile according to Ian Jacobs, director of communications for W3C, the organization would let the charter of its XHTML 2 working group expire at the end of this year and direct those resources to the development of HTML 5.
“The organic growth of HTML 5 has far superseded that of XHTML 2,” Jacobs says in an interview with SD Times. XHTML was a W3C effort to take the HTML feature set for documents, such as tables, lists and headings, and enable it to be written in XML and still work in a browser, he explained. XHTML 1 was accepted as a W3C recommendation in January 2000.
As for interoperability among browsers, Jacobs says, “We said, ‘Do it this way,’ and they went off to do their own thing.” In 2004, the Web Hypertext Application Technology Working Group (WHATWG) was formed by individuals from browser makers Apple, Opera and Mozilla to continue work on the HTML specification. That work, Jacobs says, went on outside the W3C.
“In 2007, we said we made a mistake,” he says. “We didn’t do our job of bridging communities.” That year, the W3C agreed to accept WHATWG’s work on HTML 5 as a starting point on the new specification, and the WHATWG work came under the auspices of the W3C.
5 is becoming the platform for application development, he says, and
along with CSS and SVG, will help form the operating system for the
Web. “You have scripting, graphics, HTML, with audio and video to
follow,” he says, adding that the W3C is also working to standardize an