Differences between HTML5 and HTML4

[Kristijntje]

3.1. Content Model Changes

HTML5 has defined stricter content models for elements such as div and li. These elements can now contain either "block level" or "inline level" content, but not both. This change makes HTML consistent in classifying elements according to whether they are used for structuring the page ("block level") or assigning semantics to text within the structure ("inline level")...

3.2. New Elements

The following elements have been introduced for better structure:

    *article represents an independent piece of content of a document, such as a blog entry or newspaper article.
    * aside represents a piece of content that is only slightly related to the rest of the page.
    *dialog can be used to mark up a conversation like this:

full article: http://dev.w3.org/cvsweb/~checkout~/html...rview.html

[BellisimaJ.]

3.2. New Elements

I like some of the new elements. I think it should make some things more readable/clear to the viewer, and presents the coder with more options.

[Howits]

The key differences are:

New parsing rules oriented towards flexible parsing and compatibility
New elements – section, video, progress, nav, meter, time, aside, canvas
New input attributes – dates and times, email, url
New attributes – ping, charset, async
Global attributes (that can be applied for every element) – id, tabindex, repeat
Deprecated elements dropped – center, font, strike