Which HTML5? - WHATWG and W3C Split
Found on I Programmer on Saturday, 21 July 2012

In plain terms this means that the W3C will continue to work on the HTML5 specification. WHATWG on the other hand will continue its work with HTML5 as a "Living Standard". The idea of a living standard is that it never settles down and is always being added to and refined. The task of the browser makers and the programmers using HTML5 is to try to keep up.
Overall this doesn't seem to be a good development. It will no longer be possible to say exactly what HTML5 is - the W3C's snapshot or the living standard of WHATWG.
What a dumb idea. You need a defined standard so that developers know what to work with; and what will still work next week. It will turn into a total mess when suddenly HTML is constantly changing.