There’s a little tiny feature in the newest PowerBooks where the trackpad detects a single or double fingered touch, and behaves accordingly. It’s the smallest of changes from your typical trackpad behaviour, and it sounded rather inconsequential when I read about it. The beauty of this little feature is in the using; it makes scrolling around windows horizontally, vertically, diagonally incredibly easy. On many PC laptop trackpads I’ve seen a variety of methods that allowed for specific actions based on the region of the pad you were using; dragging your finger down the very right edge would scroll the window, or tapping in the upper left corner would right-click. They’re good tries, but they just don’t hit it; Apple hits it.