Well, sometimes you may have a pop up window which you use as a target for links on your page say. So when you clicka link you get some information popping up.
So, when you minimise it, it stays there, even when a new link is clicked, so the user may notrealise something has happened.
So you make it spring back up, so they can see it!
Also you can make the window always on top.
like onblur = focus, to stop it minimizing.
-Ben. "Alright whatever man, I'll hook up the hair, but I aint touchin the ring...Cause I'm still a pla--yer"