History of HTML 

In 1980, physicist Tim Berners-Lee, who was a contractor at CERN, proposed and prototyped ENQUIRE, a system for CERN researchers to use and share documents. In 1989, Berners-Lee wrote a memo proposing an Internet-based hypertext system, which he later called HyperText Markup Language (HTML). Berners-Lee  wrote the browser and server software for a web based document system using HTML in the latter part of 1990. The first publicly available description of HTML was a document called "HTML Tags", first mentioned on the Internet by Berners-Lee in late 1991. It describes 18 elements comprising the initial, relatively simple design of HTML. Eleven of these elements still exist in HTML.  

The First Web Site

The first website was published on August 6, 1991 at http://info.cern.ch/hypertext/WWW/TheProject.html. The whole project was released to the world by Cern on April 30 1993.  In October 1994 Tim Berners-Lee founded the World Wide Web Consortium with the mission "to lead the World Wide Web to its full potential" (W3C Mission).  

Web Standards

One of the tasks of the W3C has been to develop standards for the various versions of HTML.  There have have many versions of HTML since 1991. The main versions are:
* HTML 2.0 in November 1995
* HTML 3.2 in January 1997
* HTML 4.0 in December 1997
* HTML 4.01 in December 1999
* HTML5 in January 2008.  
Martin Rhinehart has tracked the changes across all these major versions.  

Cascading Style Sheets

Early HTML was designed to display information on a web page.  It included some basic styling such as headings and bold tags.  In December 1996 the first version of Cascading Style Sheets (CSS) was released by the W3C.  Since then most web designers have tried to separate the content of a web page (in HTML) from the design of the page (in CSS).

Semantic Web

In 2001 Berners-Lee (with others) develop the concept of the Semantic Web.  He saw the Semantic Web as "an extension of the current one, in which information is given well-defined meaning, better enabling computers and people to work in cooperation" (Scientific American).  To achieve this web designers now use HTML just to convey the meaning of the content, never to provide the visual display.  Many of the visual display tags have been removed from the latest version of HTML.  By using HTML semantically the web page can be used a number ways to provide information, by the browser or screen reader for humans or by webcrawlers for search engines or mashup services.

Browsers

The most important part of web pages is how the browser will work with the HTML and CSS.  Since the beginning all the browsers have taken the W3C standards and found their own way to implement them.  This still continues which means that while most browser display old HTML and CSS the same way, the newer features are often done in different ways or using different commands.  A site like caniuse.com helps developers by listing all the new features of HTML and CSS and showing which browsers currently support each feature and what are the commands to use.

Mobiles

What Berners-Lee envisaged in 2001 is now common in the mobile environment of today.  Mobile use is growing and most well designed web sites work on mobile devices just as well as on desktop or laptop browsers.  Mobile devices are particularly suited to using the Semantic Web where information is created once and then shared with a number of applications (apps).  Now days many mobile devices use web pages heavily and it is possible to create a mobile app from a web page.  Environments like Jquery Mobile and Phonegap make this fairly easy.


Sources:

http://caniuse.com/
http://en.wikipedia.org/wiki/HTML
http://en.wikipedia.org/wiki/List_of_websites_founded_before_1995
http://info.cern.ch/
http://info.cern.ch/hypertext/WWW/TheProject.html
http://jquerymobile.com/
http://phonegap.com/
http://www.cssneuse.net/the-history-of-css.php
http://www.martinrinehart.com/frontend-engineering/engineers/html/html-tag-history.html
http://www.scientificamerican.com/article.cfm?id=the-semantic-web&page=2
http://www.w3.org/Consortium/facts#history
http://www.w3.org/Consortium/mission
http://www.w3.org/Style/LieBos2e/history/Overview.html