In a blog post, Reinventing HTML | Decentralized Information Group, Tim Berners-Lee announced a new W3C working group to reinvent HTML. This has unleashed a storm of blog posts, the majority of which you can find at the end of this article by 456 Berea St. The idea motivating Tim Berners-Lee is that the move to XML has failed because people are still using HTML 4, and something needs to be done to move people away from HTML 4.
My attitude as a teacher/writer on the topic of learning HTML/XHTML has always been that students should learn HTML as if it were XHTML. That is, students should write HTML using all the characteristics of XHTML such as quoted values, lower case tags, well-formedness and so on. The single exception to that is leaving out the trailing slash in empty elements when writing HTML. In addition, students should learn to write HTML with separation of content from presentation and without deprecated elements.
One reason I like this approach is that problems in XHTML such as MIME types, XML prologues, and so on can be avoided by using HTML, but in a way that is as clean and valid as XHTML without actually moving to an XHTML DOCTYPE. The material I’ve written on this topic teaches students to write XHTML and then transfers that set of coding rules, syntax habits, and attitudes to writing HTML.
Since any change in the rules at the W3C will occur in slow-motion, I don’t think anyone needs to worry about the code, textbooks, or methods they are using now becoming obsolete overnight. But we need to keep an eye on how this plays out, because at some point students may need to learn to write HTML/XHTML in consideration of whatever comes next in a way that takes their skills forward. I’ve found a way to teach HTML/XHTML so students write HTML according to the current standards and is as clean as XHTML. We’ll need to find a system as effective as that, if the W3C actually comes up with another specification for HTML.