It appears that the long time battle between XHTML2 and HTML5 has come to a conclusion, and HTML5 has won. Actually, HTML5 has been ahead for some time, but the w3c finally officially announced the ending of XHTML2 standards development. For a good introduction to the issue, take a look at Wired’s overview of the announcement.
This move is a good thing. It removes a distraction and helps browser makers focus their attention on one implementation. As for what it means for Web developers? As far as impact to our coding, it appears the impact should be low. As long as you code to current standards, your code should be compatible to either HTML5 or it’s XML-based XHTML5 sibling. Of course there will be some impact in learning the new language elements, but the learning curve should be relatively gentle. For those who like agonizing detail, here’s the HTML 5 spec. The HTML 4 to 5 differences article by the w3c gives you the skinny on what are the new language elements. For a higher level overview, A List Apart has an older but still relevant overview.