The W3C announced recently that HTML5 has progressed to Candidate Recommendation status. This means HTML5 is relatively stable and that web designers should feel confident using HTML5 syntax on web pages. The W3C indicated that new work and future changes will be part of the HTML5.1 specification. See
http://news.cnet.com/8301-17939_109-57559512-2/w3c-buttons-down-html5-opens-up-html5.1/ for more information.