Now imagine I'm surfing as a blind user, and I follow a link from HN, and my screen reader starts reading the page, only to be interrupted by a "take this survey" modal DIV. After a couple of times I'm turning off the JS, cos that's really annoying.

The people who make my zoom software make OSX (it's built into the operating system and it works amazingly well for me except for applications which fire events when I hover.

Following the principles of UJS and web standards makes it infinitely easier, in my experience, to develop web sites that work with screen readers and still use that advanced technology that everyone's gaga over. But if you can't write JS easily that works across multiple browsers, how do you ever expect assistive technology to be able to interpret it correctly? :)