This post was originally published on the Yahoo! Accessibility blog.
One aspect I haven't seen fully addressed in the argument for using HTML5 tags, especially when considering methods to bullet-proof methods, is user benefit. Yes, the new elements in HTML 5 (nav, footer, header, aside, section, article) give developers a more expressive language. However, if that language isn't interpreted by the browser to actually mean something then there is less, and in some cases, no benefit to the end user.
To put a finer point on this: currently browsers don't consistently translate HTML 5 elements into accessible information. You could defer the solution to that problem to the browsers. That would be a valid position if we didn't already have an viable alternative in ARIA roles. Unlike HTML 5, ARIA works now, and is consistently supported across the A-Grade. Plus ARIA is supported by assistive technology like screen readers.
What do I mean by "works now"?