I’m a UI geek and the first thing I noticed during the iPhone demo was how fun scrolling seems. With small devices and even regular sized computers a majority of our time is spent scrolling various collections of content. Only a company like Apple can step back, recognize this, and make it fun. This will no doubt engage users, bringing them closer to flow.
Easing has been around a long time. I remember learning how to do it in Flash with the aid of Joshua Davis. You could fling that scroll bar right across the screen and have to bounce right back. Then Robert Penner made everyones life easier with his ubiquitous easing equations.
I can’t help but imagine this new iPhone UI hinted at a lot of what we’ll be seeing in Leopard. I don’t know if everyone would want easing in Leopard but, if done right, it could bring to life a hella fun interface. It might also help some of us that design huge content sites :)