The W3C, which guides the standard for web development, is urging developers not to use HTML5. At least, not yet.
Development of HTML5 began in 2004. While some of the proposed specifications can already be found on the web, it won’t receive final approval for two to three years. Once ready for prime time, HTML5 should slowly replace Adobe’s Flash.
Until then, however, the W3C still has a lot of work to do, including figuring out what to do for a video codec.