The World Wide Web Consortium (W3C) comprises a consortium that produces standards for the World Wide Web. Tim Berners-Lee, the original creator of the HTTP (HyperText Transfer Protocol) and of HTML (HyperText Markup Language) which form the basis of the Web, heads the Consortium.
A standard goes through the stages Working Draft, Last Call, Proposed Recommendation and Candidate Recommendation. It ends as a Recommendation. The Consortium leaves it up to manufacturers to follow the recommendations. Many do.
See also: Cascading Style Sheets, DOM, SVG, XML, WAI