We strive to make our website as accessible and usable as possible. We do this by following Section 508 and the Web Content Accessibility Guidelines (WCAG 2.0) produced by the World Wide Web Consortium (W3C, the web's governing body).
Section 508 is a legal requirement and WCAG is a set of checkpoints and guidelines that help ensure that websites are designed and written properly. For example:
Images have alternative text (so if you can't see the image you can still read the text).
Color contrast between the foreground and background is sufficiently strong.
Text resizes according to user preference.
Headings are correctly used (they're not just ordinary text made to look big and bold).
Links make sense by themselves (e.g. no links that just say "Click here" or "More...").
Tables are used for laying out tabular information and have proper headings and summaries.
For those familiar with Section 508 and WCAG, we aim for AA compliance across our site. We also look for opportunities to meet AAA compliance.