The W3C provides guidelines based on best practice, regarding how websites and web pages should be structured and created for long–term durability. The W3C validation is just a standard for specified machine language, checking web documents, spelling, grammar, syntax, and proofreading.

XHTML is the newest standard for this hybrid markup language designed for web documents. It is a combination of classic HTML and advanced XML. Validation is in fact, the process of checking documents against this formal standard. Converting your HTML web pages to XHTML takes time. This will definitely help your website in the future. Although the easiest way of creating XHTML pages is to start a new project, redesigning and updating old pages could also be a viable solution.

The rules W3C outlines are not compulsory since they don’t have a certification program, but there are reasons why you should bring your website into compliance.

Main advantages that derive from W3C compliance:
  • Your website will be more easily accessed by people with disabilities and the user experience will be improved; 
  • W3C validation helps you reduce the amount of coding on your pages thus emphasizing the importance of content. Your site will have the chance to get indexed and as a result get higher rankings in the most important search engines, since spiders are known to crawl websites with relevant content;
  • Your website can be easily accessed from different devices – PCs, laptops, PDAs, cellular phones, etc.;
  • Validation is fully compatible with a wide range of dynamic pages, scripting and active content, multimedia presentations, etc.;
  • Different current and future browsers will display pages in the same way, or at least in a very similar fashion.
Not all errors are so severe as to cause problems with search engines rankings. Take the time to run your web pages through a validating tool, after you’ve made all the necessary modifications.

Fortunately there are free services that allow you to check your documents for compliance with web standards. The W3C's free online Validation Service (validator.w3.org ) is used by many professionals to ensure their sites comply with web standards.