In trying to find information on web accessibility issues, I searched around for articles in different places. Most sites said the articles they linked to were outdated, but finally one led me to the W3 Web Accessibility Initiative (WAI). According to their site, the WAI "develops strategies, guidelines, and resources to help make the Web accessible to people with disabilities. The following WAI resources are intended to provide basic information for people who are new to Web accessibility." They look for volunteers and help from whoever is willing to contribute, so it is not simply a small group of people doing all this work.
More information can be found at http://www.w3.org/WAI/ and http://www.w3.org/WAI/intro/accessibility.php