Quick Tip: Speed up entering a url in Mobile Safari.

In Mobile Safari for the iOS devices, such as your iPhone or iPad, you can enter a new url without tapping the x that clears the url field.

For Example:

If you already have say apple.com open on you iphone and you want to go to newmacuser.com. All you have to do is tap the url bar and start typing. Mobile Safari is smart enough to know that you want a new url and clears the old one for you.