HTML5 is the latest version of Hypertext Markup Language, the code that describes web pages. It's actually three kinds of code: HTML, which provides the structure; Cascading Style Sheets (CSS), which take care of presentation; and JavaScript, which makes things happen.
What's so great about HTML5?
HTML5 has been designed to deliver almost everything you'd want to do online without requiring additional software such as browser plugins. It does everything from animation to apps, music to movies, and can also be used to build incredibly complicated applications that run in your browser.
There's more. HTML5 isn't proprietary, so you don't need to pay royalties to use it. It's also cross-platform, which means it doesn't care whether you're using a tablet or a smartphone, a netbook, notebook or ultrabook or a Smart TV: if your browser supports HTML5, it should work flawlessly. Inevitably, it's a bit more complicated than that. More about that in a moment.
What does HTML5 do?
We've come a long way since HTML could barely handle a simple page layout. HTML5 can be used to write web applications that still work when you're not connected to the net; to tell websites where you are physically located; to handle high definition video; and to deliver extraordinary graphics.