In his recent book - The Truth about HTML5, Luke Stevens argues that many of the HTML5 elements (header, footer, nav, section, aside, for example) should not be used nor taught in our classes. He believes that most browser manufacturers will not implement these elements in any future releaseand they are artifacts from discussions of many years ago. What are your thoughts on this matter? Should we be teaching these elements? Why or why not? As far as I know, most of the elements in the above list are not recognized by any modern browser. Luke argues we should be using ARIA roles instead. Yes, these elements are included in Dreamweaver CS 6.