Normally I formally define the target audience for a site.
The definition includes browsers in use.
It's useful if something like IE5 comes up. You can say, discontinued at
whatever-the-date-was and currently
0.0001% (or whatever) of Internet users -> Forget it. (Without something like that web site design is limited.)
I suspected that XHTML 5 was dead for me. W3C says 2012 but the guy who is doing the work (Ian Hickson) says 2022. To me that means 2022 is the date for completion.
If you look deeper into waht he means, he says HTML 4 is not finished, so it's a strict test for completion.
From some quick tests yesterday (I couldn't find test pages for what interested me, so I had to write my own) I'd say that:
1) IE8 and the current other browsers probably
recognise X/HTML 5 documents. (Not formally checked but all act on some bits of ...5).
2) For the programmatic bits IE8 implements
dom storage and
xdm (or rephrased, give a better way than cookies and allow controlled cross page programming). FF seems to implement the xdm stuff. See
http://samples.msdn.microsoft.com/ietes ... /html5.htm for the test suite.
3) For things like
time,
meter and
progress, there may not yet be implementation, but some forms of implementation I wouldn't see so thats unclear.
4) For the obvious (and presumably easy) things like
nav, header, footer, menu, aside... There is a lot of implementation on the browsers I tested (IE8, FF, Opera, Chrome, Safari) but there are bits missing. (
2009/03/01 On review of the test page that I found for menu etc. I'm not convinced there's much implementation of anything except menu, yet. It is already possible however for designers to write pages that emulate these things on non-IE browsers.)
This is a provisional analysis. Maybe an hour. I was expecting to see it all done by somebody else so was pretty surprised that I had to answer these basic questions for myself. The conclusion is that X/HTML5 will be
usable, in some sense, when IE8 comes out and a year or 18 months after that can be used by those who keep right away from the bleeding edge.