Evidently, there's a way for web app designers to add a meta tag to their web pages so that on the iPhone,
...if you use the Add to Home Screen feature, it will launch as its own standalone app, with no Safari browser chrome. It’s a way to make site-specific browsers for the iPhone. They run as their own processes, outside MobileSafari.
I've tried adding several web apps to my home screen in this way, but when I launch them Safari still seems to have all the normal chrome:
I was assuming that the URL and search bar at the top would disappear, as would the navigation bar at the bottom. If that's not what full-screen Safari means, then what is it?
Next, I suppose it's possible that the sites I've tried don't use the tag; here are some of the mobile sites I've tried: