Web Accessibility Initiative (WAI)
When developing web sites, making them as accessible as possible is crucial, both to people with different kinds of disabilities as well as to all kinds of different devices, web browsers and screen readers etc.
Why? Out of respect for the user, while making the web site available to as many users as possible.
You need to be aware of the fact that the web site will not look the same to all visitors, not all UAs handle CSS and other things. The solution isn’t to code in HTML 3.2 and avoid using CSS and JavaScript, since that’s just plain dumb.

