I don’t remember the details, but I stumbled upon the WAI-ARIA? project when it was a hatchling, and almost no one I knew had heard of it. It’s been over 2 years, the bird has left the nest, but it still seems to be flying under many people’s radar. It really should be an important piece in the designer’s repertoire. I’ve written about this at much greater length while I was doing an independent reading in Web Usability and Accessibility as part of my graduate studies. AJAX? messes with a web page’s “DOM”? in ways that are hidden from the user of the page by design. ARIA is meant to talk to assistive technologies and keep track of all such changes, communicating them to the software, or responding to custom designed hardware to do things those of us with so-called normal abilities take for granted. To do this, ARIA defines and then makes use of roles—e.g., this is a toolbar, this is a menu item; states—this panel is folded or invisible, this one is displayed; and properties—this menu has a drop-down, this one a pop-up.