First a small introduction to the HTML 5 introduction; If you are wondering why I didn't published during the last 2 weeks, the reason is a great vacation in New York - in one simple word - Insane. (pics will be delivered on the following days).
Now to our topic - HTML 5. We all used to (and still) work and know greatly HTML 4 - which actually is exists something like a decade, but HTML 5 is stands in front of us (but is still to come - the work is still on progress according W3C) and comes to simplify our life (as client developers - side by side to the server hard work of course).
Indeed, HTML 5 will going to introduce a whole new set of elements that will make out lives to much more easier, also based on the fundamentals of HTML 4. The main innovations comes to replace the HTML 4 basic elements as DIV for an instance (which is one of the most used elements) with simplify elements that will use to represent the purpose of each one of them, like header, footer, section etc. - each one of then is a new well known element in the new language. A page rendered with HTML 5 could be shown like the following code snippet:
<body>
<header>...</header>
<nav>...</nav>
<article>
<section> ... </section>
</article>
<aside>...</aside>
<footer>...</footer>
</body>
One of the new innovations is the language definition. It means that HTML 5 is being defined in terms of the Document Object Model (DOM) as a tree representation that will be interpreted by the browser. This definition came from the idea of separating the language itself from its syntax, which can be defined independently.
As we know from previous HTML formats (HTML 4), there are 2 kinds of syntaxes: the HTML itself which is serialized as plain HTML or XHTML which is serialized as XML.
The coin has two sides - each holds its benefits (you also aware of it right? ;)).
The benefits of using HTML 5 (which based on the familiar HTML) are the compatible of existing browsers and the second thing is the acquaintance of it by the authors (in our case - people like me and you!).
On other hand, using XHTML 5 will encourages authors to write well-formed markup, which some authors may find easier to maintain and Integrates directly with other XML vocabularies.
This is still under consideration, so we have to wait to the decision...
Some more tutorials and information regarding HTML 5 you can find in the W3C site here.