Use Open and Supported Standards
W3C Web Standards support interoperability and give all users more options in accessing and using web content. People with disabilities use a more diverse set of technologies to access the web than the general population.
Forward and Backward Browser Compatibility
Use of web standards supports forward looking web design. For example, as computer monitors increase in pixel density, many current web pages will shrink in size eventually become unusable for all users. The use of web standards allows web pages to adapt to these and other changes in display technology.
Support for Pervasive Computing Technologies
The use of web standards allows cell phones, PDAs, and new voice browser technologies to access and use web resources without the need to develop special versions or use problematic conversion tools.
W3C Web Content Accessibility Guidelines 1.0 and Section 508 provide guidance in the HTML markup issues related to accessibility.
Specify the DOCTYPE the page uses to validate HTML coding