Michael,
We don't offer it yet. We need to add the ability to enter an application in a certain state, but in a way that works not just with URLs. There are circumstances, like a bookmarked HTML5 app on the home screen of a mobile device, or an HTML5 application in a native shell like PhoneGap, where URL is not available to save a state and bring it back, in these cases for example, local storage would be more appropriate.
URLs are obviously very important for bookmarking and sharing, especially on desktop, and we'll support that as well. Could you give me the context where you need it?
Thanks!
Benoit