What is the impact of HTML5 on XHTML (the XML serialization of HTML)?
The HTML5 specification defines two syntaxes, an HTML syntax and an XHTML syntax. The HTML syntax is intended to be served using the text/html media type. The XHTML syntax is intended to be served using the application/xhtml+xml media type. The Polyglot Markup: HTML-Compatible XHTML Documents specification (a work in progress) describes documents that conform to both syntaxes and can therefore be served as application/xhtml+xml or text/html.