UX Niceties: iOS 7's Safari auto-hide address bars
Google's Chrome on iOS has had an auto-hide URL bar since the beginning, but it always felt in my way. Every time you scroll down, the bar would reappear again -- taking up valuable screen space. The interaction was too simple: drag up and the bar would scroll away, drag down and the bar would reappear. The address bar was being smart but not smart enough.
In Safari, the address bar auto shrinks when you start scrolling up (it also leaves the title of the page so you know which page you are on and is also translucent so it's not visually overbearing). The difference is that the bar doesn't expand to its original size whenever you scroll down the tiniest bit, but only does so when you give the page a downward swipe where you let go at the end of the swipe. In my browsing experience, this has meant that regular drags downwards to reread something didn't make the address bar expand. This is good.
Another good interaction is that the address bar and the navigation bar at the bottom reappear upon reaching the bottom of the page, which is logical, as you probably want to navigate somewhere once you reach the end of the page. Furthermore, the bottom navigation bar slides in after the content as if were part of the page, and not over the content so as not to block said content.
One last thing about the address bar and controls bar is that you can tap the top and bottom area of the screen (where the browser chrome would be if fully expanded) to make navigation bars appear. This means you don't necessarily have to scroll down on the content to get the bars to reappear and instead activate the buttons exactly where they will appear. You might be thinking, what if there is a link near the top and bottom pixels? Well, you can just hold the link for a fraction of a second longer which is interpreted as a more deliberate press and the link will be opened instead of expanding the address bar and navigation controls.
The downside of all this ingenuity? You now have to press twice on the status bar area to get to the top of the page.