I've been looking into Accessiblity lately as well as the Microsoft Accessibility Inititive . The American's with Disabilities act requires that Federal Websites be accessible to all . The W3C has a number of pages on Web Accesiblity, under the WAI working group. These guidelines  and  offer a lot of guidelines and techniques  on how to write HTML that is up to snuff and accesible to all. These extra tags and techniques allow Screen Reading Software  that linearize HTML and provide additional context, like which labels go with which text boxes. You can test your website for accessiblity with online tools like Bobby.