While HTML5 has been in use for a few years, the fact that it wasn’t a full W3C Recommendation (in layman’s terms, an official release of the next version of HTML) provided leeway for browser developer interpretation and understandably hindered more widespread adoption. All standards need to continuously evolve to remain relevant and useful so this is not the end HTML development, but now there is a stable specification that will help normalize browser support and encourage reluctant app developers to invest more fully in HTML5.
From the W3C press release:
“Today we think nothing of watching video and audio natively in the browser, and nothing of running a browser on a phone,” said Tim Berners-Lee, W3C Director. “We expect to be able to share photos, shop, read the news, and look up information anywhere, on any device. Though they remain invisible to most users, HTML5 and the Open Web Platform are driving these growing user expectations.”
HTML5 brings to the Web video and audio tracks without needing plugins; programmatic access to a resolution-dependent bitmap canvas, which is useful for rendering graphs, game graphics, or other visual images on the fly; native support for scalable vector graphics (SVG) and math (MathML); annotations important for East Asian typography (Ruby); features to enable accessibility of rich applications; and much more.
For more details read the full release.