I tend to add a lot of web apps for function and usability testing, and usually end up with several pages of icons. In order to beter organize them I move them from one page to another. Moving an icon to a different page is sometimes is a problem. I slide the icon to the edge but sometimes it just doesn't easily move to the next page until I try two of three times. Or it won't go at all if the next page is full. A perfect solution to this is to simply move one icon out of the dock at the bottom of the page. Then move the icon you want to move into the dock. Now, just flip to the page you want to move the icon to and slide the icon out of the dock. If you have three+ pages of icons, this is by far the easiest way to move them back and forth.