Here’s a rough transcript, if you don’t want to watch it:
Neat! Basically, you can add markup to your HTML, and it will help applications like VoiceOver allow people to use your site more easily, even if it uses a lot of Ajax. This is super cool, and for me, mitigates one of my main complaints against using SPAs. Of course, WAI-ARIA isn’t really Ember’s job; you’ll have to make the HTML be output in the right way yourself. But it makes me really happy to know that people with disabilities don’t need to be left out of the rich-client portion of the web.