W3C is short for the World Wide Web Consortium, an international consortium of companies founded in 1994. The purpose of the W3C is to establish language criteria that ensures compatibility among industry members which reduces incompatible versions of HTML.
Being W3C compliant ensures that your website maintains a consistant look, feel, and layout across many browsers and different platforms. Compliance also ensures accessibility for the disabled. In recent polls less than 7% of all websites are W3C compliant. The question which remains for discussion is, are these standards crucial to the webs existence?
Would you like check how your website measures up? Use the W3C Markup Validation Service: http://validator.w3.org/
The latest released standard by W3C is known as the RIF (Rule Interchange Format). For more information please visit: http://www.w3.org/.