What's the key difference between HTML 4 and HTML 5?

Question

What are the key differences between HTML4 and HTML5 draft?

Please keep the answers related to changed syntax and added/removed html elements.

Answer 1

You might be interested in this list of HTML5 elements and attributes.

Also, please note that it's "HTML 4", not "HTML4". Indeed, for HTML 5, both variants are used, but there is an important difference in meaning. HTML 5 refers to the name of the W3C specification, whereas "HTML5" is the document type of those HTML files with a text/html MIME type that follow this spec. The same goes for XHTML 5 vs. XHTML5.