I read the future of HTML the other day on developerWorks. It is written by Edd Dumbill from XTech. Nice to know IBM supports such content! Large companies probably just bet on multiple horses.
There are some small flaws in the article thought. Here are my comments:
XMLHttpRequest is indeed used by (god forbid) “Ajax applications.” However, contrary to what the article suggests it is one of the ways forward. WHATWG actually defines the XMLHttpRequest interface and the W3C Web APIs Working Group is going to copy that and rubber-stamp it with the word “Recommendation” and a W3C testsuite. (Well, that would be the easy route.) It might be noteworthy that the article actually does mention that WHATWG standardizes XMLHttpRequest. The introduction just seems to contradict with that.
canvas is not the only feature from “HTML5” that has implementations. Cross-document messaging has at least one implementation and various features that have been clarified are implemented like the Window, Location and XMLHttpRequest object et cetera. Also, the document is not yet stable so starting implementations based on certain sections might not be so wise. Eventually all parts which do not get implemented will be clarified, dropped or simplified though. The same happens with Web Forms 2 at the moment. (I believe most of the draft made it. Some parts regarding form submission are altered and a lot of mistakes have been fixed.)