HTML 5 includes a handful of new structural elements that are designed to make markup more meaningful. You can use these elements today; they don't really do much, so browsers don't need to explicitly support them. And it takes only a little trickery to make them work even in IE.
From a site visitor perspective, the new elements are essentially useless, but don't let that get you down: their reason for existence is to make web page code more meaningful.
Using these tags can make your web pages more understandable by both humans and robots: Humans (even you!) who are looking at your web page code and trying to understand it will have more hints as to the purpose of various parts of the page.
Robots, notably search engine spiders, will eventually find the hints provided by these tags to be helpful in understanding what a web page is about.
Screen readers and other assistive devices for site visitors with disabilities will be able to better choose what content to skip and how to jump around.
These new structural elements have been grouped into five different categories with definitions and brief descriptions for each element.