I can’t even begin to tell you how useful it is to quickly scroll up to the top of a window on the iPhone. Since the screen is so small, you can end up scrolling down a lot when viewing a webpage, reading an email, or sending a text. In Safari, in order to type in a new URL in the address bar, you have to go back to the top. In Messages, you can quickly call or email someone by going to the top.
On the iPhone, just tap the status bar at the very top and you’ll be bought to the very top of the page. Note that you want to tap on the status bar that has the time listed. Saves a lot of finger swiping!
"iPhone Tip – Scroll to the Top"
Reference : online-tech-tips.com