The World Wide Web Consortium (W3C) is an international consortium where Member organizations, a full-time staff, and the public work together to develop Web standards. W3C's mission is: To lead the World Wide Web to its full potential by developing protocols and guidelines that ensure long-term growth for the Web.
WAI, in coordination with organizations around the world, pursues accessibility of the Web through four primary areas of work: technology, tools, education and outreach, and research and development.
7.1 Until user agents allow users to control flickering, avoid causing the screen to flicker.
WCAG 2.0 allows more movement within defined parameters (for instance)
Three Flashes or Below Threshold: 2.3.1 Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds. (Level A)
1.4.3 Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 5:1 , except for the following:
Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 3:1 ;
Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
Logotypes: Text that is part of a logo or brand name has no minimum contrast requirement. (from the Dec 2008 Draft)
WCAG 1 - Provide clear and consistent navigation mechanisms -- orientation information, navigation bars, a site map, etc. -- to increase the likelihood that a person will find what they are looking for at a site.
WCAG 2 - Provide ways to help users navigate, find content and determine where they are.