In part 2 of my series entitled “The Top 5 Questions People Ask Me About HTML5,” I’m going back to basics: “What is HTML5?”

HTML, as you may know, stands for Hypertext Markup Language.

Hypertext is text that contains references (links) to other text that can be immediately accessed by the reader. For example, you may be reading an article about HTML5, and the author may say that much more information about this topic is available in his book about HTML5. The text is much more than just text, because it could, in theory, link to all other text on the web (eventually) from that link.

Sidebar: Some Hypertext History
The word, Hypertext, was coined by Ted Nelson in the 1960s to describe the main idea of a proposed system he called Xanadu (which has nothing to do with the movie, Xanadu). In Xanadu, every document would link to its source documents, and referenced text, images, video and audio would be used directly from those source documents, rather than authors copying and pasting content into new documents and losing the history attached to the content. The details of Xanadu are beyond the scope of this newsletter, but make for interesting reading — and Ted Nelson is one of the more colorful and interesting figures in Internet history.

Markup Language is a way of annotating text using special characters. For example, to say that certain text represents the title of a document, you can “mark it up” with the HTML title tag, like this: <title>Welcome to my home on the WWW</title>.

So, at its most basic, HTML is really just a system for annotating text andcreating links between text.

However, when millions of people know this language and when you combine HTML with a viewing application called a web browser and distribute HTML documents over the Internet, HTML becomes much more powerful.

Because it’s so simple to learn, early versions of HTML (in the mid-to-late 1990s) gained very widespread use, and the Web was born.

But then, in the late 90s, something strange happened: the geeks decided that webpage creation needed to be more of a rarified skill and that we couldn’t have just anyone learning how to do this stuff. This is how a language called XHTML was born.

XHTML was supposed to be a cleaned-up version of HTML that would require authors to write “well-formed and valid” markup and check it with syntax validators or else their webpages just wouldn’t display. For programmers, this sounds perfectly natural. We’re used to a world in which you need to speak the computer’s language or else things don’t work. But, this isn’t the way of the Web, and very few people ever actually used XHTML in the way it was designed. I refer to XHTML as the language that very nearly killed the Web.

Around 2005 or so, a group of browser-makers decided that they were tired of waiting for the bugs to be worked out with XHTML and they started working on a new revision of HTML, HTML5. One of the main ideas behind HTML5 is that webpage authors are going to make mistakes. But, if every browser handles markup errors in the same way, it’s not that big of a deal.

Because it shifts the burden of responsibility for compliance with standards from the author to the computer, HTML5 is a much more human-friendly language. As a result of HTML5, and the excitement generated by it, the Web is currently going through a giant burst of change and innovation.

In my next newsletter, I’ll take on another one of the top 5 questions I get about HTML5. Do you have a question? Let me know!

What is HTML5?