HTML Evolution

1990-1995
Hosted first at CERN, and then at the IETF.

1995 
HTML 3.0.

1997 
HTML 3.2.

1997 
HTML 4.

1998 
DOM Level 1, HTML evolution stopped.

2000 
HTML 4 in XML, called  XHTML 1.0.

2000-2003 
DOM Level 2 Core and DOM Level 2 HTML.

2003 
The publication of XForms, sparked a renewed interest in evolving HTML itself, rather than finding replacements for it. 
Start to realize that XML cannot replace HTML.

2004 
DOM Level 3 specifications published but the working group being closed before all the Level 3 drafts were completed.

2004 
The proposal to reopen the evolution of HTML was rejected by W3C. Because they want to focus on XML to replace HTML.

2004 
WHATWG(Web Hypertext Application Technology Work Group) was found by Apple, Mozilla, and Opera to work on evolution of HTML.

2007 
W3C formed a working group chartered to work with the WHATWG on the development of the HTML5 specification. 
Realize that the XML's deployment as a Web technology was limited to entirely new technologies (like RSS and later Atom).

2011 
WHATWG wanted to continue working on a Living Standard for HTML, continuously maintaining the specification and adding new features. 
However, W3C wanted to publish the HTML5 recommendation.

2012 
W3C decided to wait and continue picking up new features and bug fixes from WHATWG.

2012 -present.