Alex Sexton answers this and other extremely important questions on his site whatis.partofhtml5.com.

I can already see the new html5 advertising wave. Ads blinking everywhere until we all have a stroke.

For anyone seriously looking at html5: go to html5rocks.com. The slideshow has great examples on almost every aspect of html5.

And if you want to know what’s really included in html5 go to the WHATWG. They list everything the W3C does, but also have tech that’s connected to html5 but not in the actual spec.