HTML5

Even well-formed HTML pages are harder to process than they should be because of the lack of structure. You have to figure out where the section breaks go by analyzing header levels. Sidebars, footers, headers, navigation menus, main content sections, and individual stories are marked up by the catch-all div element. HTML 5 adds new elements to specifically identify each of these common constructs:
* section: A part or chapter in a book, a section in a chapter, or essentially anything that has its own heading in HTML 4
* header: The page header shown on the page; not the same as the head element
* footer: The page footer where the fine print goes; the signature in an e-mail message
* nav: A collection of links to other pages
* article: An independent entry in a blog, magazine, compendium, and so forth

なんか色々elementが増えるんですね。