1. New Doctype: The simpler doctype declaration is just one of the many novelties in HTML5. Now you need to write only: and this is it. The syntax of HTML5 is compatible with HTML4 and XHTML1, but not with SGML(Standard Generalized Markup Language).
2. Geolocation: Best known for use on mobile devices, geolocation is coming with HTML5.
I made a quick little example to read a YouTube user’s video feed that really easy to use. To request a feed of all videos uploaded by another user, send a GET request to the following URL. This request does not require authentication. https://gdata.youtube.com/feeds/api/users/userId/uploads. In the URL above, you should replace the text userId with the user's YouTube user ID.