In a great article with extensive, working demonstrations (you need a modern browser — no I.E.), L. M. Orchard demonstrates the new drag-and-drop facilities in html5.

He’s even put together an outline editor where you can move items and change the hierarchy entirely by dragging. He demonstrates dragging not only within the browser window but between windows and even between the browser and other applications.

The code (javascript) for these demonstrations is remarkably light and straightforward. This kind of facility, that allows developers to bring web applications to a new level, is going to create a popular demand for thorough browser support of html5. As a result I think this standard will be adopted an order of magnitude faster than previous standards, such as xhtml, whose advantages were more subtle.