W3C:

2008-06-10: The HTML Working Group has published three documents: HTML 5, HTML 5 differences from HTML 4, and the first public draft of HTML 5 Publication Notes . HTML 5 introduces features for Web application authors, new elements based on research into prevailing authoring practices, and clear conformance criteria for user agents in an effort to improve interoperability. See the diff-marked version showing changes made since the 22 January 2008 draft. Learn more about the HTML Activity. (Permalink)