Ajax History Control

Hey All,  I just ran across an ajax control I hadn't seen before.  It's a history control.  The basics of it is that you use it to track steps made in the progression of a page with partial postbacks.  Like paging in a grid for example.  Then the control allows you to logicly go back a step in the partial postbacks when the user presses the back button.  Sounds cool, can't wait to try it.  Here is the url for the rest of you to give it a gander.  http://asp.net/learn/ajax-videos/video-149.aspx