IBM Equal Access Accessibility Checker - Opinions/experiences?

[ThunderPerfectWitchcraft]

There is a Firefox Add-On available to check for problems regarding the accessibility of a website, called the IBM Accessibility-Checker.

When I did a little project a while back I tried to use it to make the whole thing accessible (at least I hope so, I'm yet to get feedback about it :). My main page got some violations; reddit and github got many, this board here has over 80 violations. Are people around who know about accessibility for visually impaired people? Do you attempt to make your page accessible? What do you think about this tool for automatic checking - do you think it is sufficient to assume that a page that got no violations is usually usable for people who use a screen-reader (or similar devices), or do you think this is to imprecise? How serious are those "violations" - are they sure or likely to break the usability for impaired visitors, or are they usually rather nuisances? And what are your impressions about the development of the accessibility of websites in general?

[varve]

I think turning off CSS and image loading, and trying to use only a keyboard to navigate your site will show you a *lot* of the accessibility problems that a screen reader user might encounter. Because that's basically what they're doing, but with the text you see being read aloud to them.

(I'm told it also prefaces the element types with their name, so for example an image alt text starting with "image of" will be spoken as "image: image of", and buttons and links likewise are introduced. The screenreader-using folks I've talked to said for image descriptions, don't say what kind of image it is unless that's actually relevant, for example it's a painting or sketch, and if it's a functional or informative image focus the alt text on that instead of on what it looks like.)

I'm not surprised this site got loads of accessibility violations though.