Accessibility Standards and Guidelines

Section 508 Standards and the Web Content Accessibility Guidelines (WCAG) Guide Accessibility Practices in the United States (1)

On the legal side of web accessibility, the Electronic and Information Technology Accessibility Standards (part of the 1998 Amendments to Section 508 of the Rehabilitation Act of 1973), known as Section 508, lay out the requirements that all federal agencies (and vendors providing services to the federal government) of the United States must follow.
Some state and local agencies have also adopted the Section 508 standards. For example, in California, if local government agencies, places of higher education, or nonprofit organizations receive state funding, they must comply with Section 508.
The purpose of the Section 508 Standards is to ensure equal access to electronic and information technology (including websites) for users with disabilities. That is, to ensure that users with disabilities are able to access and use information quickly and easily.
Section 508 Standards are derived from WCAG 1.0, but there are differences between Section 508 Standards and WCAG 1.0.

WCAG 1.0 was created by the World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI) as a set of technical recommendations for accessible web design.
The WAI (the body responsible for creating the WCAG) was created specifically to improve the accessibility of the web for people with disabilities.
WCAG 1.0 has been either taken directly as, or used as a basis for, the accessible web design standards of many countries.
U.S. law has required website conformance to WCAG 1.0 in several cases of disabled users vs. commercial companies with websites.
WCAG 2.0 is to be an updated version of the WCAG, but is still a work in progress.

(1) Waddell, Cynthia. "Overview of Law and Guidelines", in Thatcher, Jim, Web Accessibility. FriendsofEd, 2006, pp. 63-66.