The main difference between Hyper Text Markup Language (HTML) and Extensible Markup Language (XML) is that HTML is a markup language used to create web pages and XML is also a markup language but it is mainly used for information sharing mainly among those who are connected to the Internet. HTML was created by Tim Berners-Lee as a way for him and several colleagues to share research information (Wikipedia, 2006). Early versions of HTML were based on flexible syntax rules. HTML code written using these older rules would not be considered valid using today's standards. HTML was first published as a language in 1993. The standards for HTML have been continually modified and updated over the years since its creation. Version 4.0 was published in 1997 by the World Wide Web Consortium (W3C) and the current version is 4.01, published in 1999 (Wikipedia, 2006). Since the publication of version 4.0 in 1997, the W3C has focused on the development of XHTML, an XML-based equivalent of HTML. HTML used different types of entities such as attributes, character references, data types, and attributes to format a web page. Web pages are created using elements called tags. Tags are predefined by HTML and are used to define how a web page will be presented in a browser and control elements such as background color, font size, type, and color. Tags are also used to insert links into a web page allowing the user to visit specific pages on different websites or different pages within the same website. Tags also allow the designer to include various multimedia presentations such as photos, music, and video files. Markups are grouped into smaller categories known as structural, presentational, and hypertextual (Wikipedia, 2006). Structural markups define the physical layout of a page, where various data should be displayed, and other structural settings such as the use of a heading tag such as "H6" which defines the size of the text between the H6 and H6 end tags. Presentation markups define the appearance of the text, for example some words will be bold or italicized. With the 4.0 publishing rules most presentation markup tags have been depreciated (Wikipedia, 2006) and the use of cascading style sheets is recommended. Hypertext markups use anchor tags and are used to direct visitors to a different location within the same page or site, and are also used to direct visitors to pages on other sites.