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

From Wikipedia:

• 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