HTML 5, platforms of online applications

To replace HTML 4, as the format of Web pages, the W3C, which sets the standards of the Web, has taken a specification started by the WHATWG.
This new format is implemented progressively by all browsers is designed for Web applications and adds both new tags and new features. It is now a successor to Flash and Silverlight.

JSON and HTML 5 against Silverlight and Flash

HTML 5 vs Flash and Silverlight

Applications and games in canvas

The specifications. The definition of the format is splitted into several documents.
But who define HTML 5? Is the future format of billions of webpages decided by a single person?
Security issues with HTML 5.
HTML 5 as the interface of a computer.
XUL vs. HTML 5. XUL is now history. How it compared to HTML 5?
Tools. Libraries and other tools.