The Difference Between the WHATWG and the HTMLWG
In the beginning the web was chaos and blink tags. Out of the chaos came the World Wide Web Consortium, better known as the W3C. The W3C oversees web standards like HTML and CSS. The HTML Working Group (HTMLWG) is the group within the W3C that’s charged with creating the HTML standard.
After the release of HTML 4.01 in 1999, the HTMLWG announced it would pursue an XML-based version of HTML, dubbed XHTML 2.0.
Unhappy with the direction the HTMLWG had chosen for the future of HTML, Mozilla and Opera formed the WHATWG to pursue the future of HTML (sans XML). Over time other browser makers like Apple joined the WHATWG and HTML5 was born. Microsoft was invited to join, but declined citing patent concerns (Microsoft is a member of the W3C).
Eventually the W3C’s HTMLWG realized that XHTML 2.0 was impractical and it stopped work on the fledgling spec to focus its efforts on the WHATWG’s HTML5 spec.
Today the two groups work in tandem, sharing an editor, Ian Hickson. The WHATWG classifies its spec as a “living standard,” and no longer uses version numbers. The W3C’s HTMLWG pulls from the WHATWG spec to create “snapshots” that provide implementors (like browser makers and web developers) with a stable, solid spec. Because the HTMLWG must ensure interoperability across a wide range of devices and browsers — desktop, mobile, televisions and more — it typically moves much more slowly than the WHATWG.
The HTMLWG recently announced that HTML5 will be complete and a recommended spec in 2014. The WHATWG continues to work on its HTML spec and eventually the HTMLWG will likely pull out a subset of those features and develop them under a new version number. For now, the HTMLWG is unofficially referring to this future version of HTML as “HTML.next.”