Does HTML Validation Help?

Using standard HTML code means ensuring that the web site is written in 100% correct syntax. W3C, the World Wide Web Consortium has published specifications regarding HTML/XHTML and guidelines on how to use them to the best effect. W3C's involvement in this particular area of web development had primary as purpose the standardisation of correct HTML code usage.

Validation of HTML code
For web developers eager to create standard compliant web sites, W3C has created a validation tool called the Validator. The Validator parses the source code of a html file and establishes whether it validates as HTML/XHTML document or not. The output reports any errors found during the process in order to help developers easily identify and fix them.

Importance of validation in accessible web design
One of the reiterated recommendations of W3C is to always validate the web pages and correct them so as they become standard compliant. But why would people go to all that trouble? Parsing every web page, writing down changes, implementing them, parsing them again until 100% validation is obtained takes time and patience most of all.

Although validation does not guarantee it, standard compliant pages stand higher chances of being compatible with various browsers. This increases overall accessibility by ensuring the web site is functional and fully visible to all users on all browsers. Alternate browsers for disabled people read the source code line by line. By ensuring that the website uses correct code, one can prevent glitches or errors which may arise during this process.
Search engines can index more easily pages that are validated than those that are not.

Conclusion
Code validation does not help users as such but if done and if using standard HTML code, the web site can reach and be accessible to more people, users who use other browsers or platforms.