John lays down the criticism on they way the W3C is approaching HTML5. He (rightly, IMO) argues that adding new elements is not the way to make HTML5 backwards nor forwards compatible. Toward the end of the article, he suggests that adding new attributes might achieve both goals. Seems logical to me.
Eric goes into detail on why he chose HTML5 for the AEA site, and what some of the differences are compared to what we already know.