Well now that somebody else bumped the thread, what the hell: all government sites have to be 508 compliant. Any site that you make can be as incompliant as you want. WDF isn't even XHTML-compliant (ironic when you think about it; WDF v4's forumhome will be).

Really the only major thing is accessiblity for the vision impaired. That means images without text, thoughtful page layouts, etc.

Try viewing your site in Lynx then reading aloud. That's a crude way of interpreting how a vision-impaired person interacts with your site.

filburt's right, I've worked with a few people who were partially blind and used screen readers, and you'd be surprised at how few of the pages out there are even navigable at all. Many pages use a lot of abbreviations or no clear markings of where links/images are and it is all very confusing to anybody using a reader...

I work for the government, and probably 90% of the pages on our site aren't compliant at all. Most of the web designers (there are probably 25+ of them in our organization) are incompetent, and the ones who do know stuff aren't able to implement anything because of the bureaucracy involved in changing the status quo. It's all quite sad.