Free focused scroll is a driver for the trackpad on Apple PowerBooks. It is an alternative to SideTrack and an improvement upon iScroll2. It achieves its advanced features by running the trackpad in what is called "absolute" mode. This means that the driver can tell exactly what part of the pad your finger is touching. The Apple driver (and iScroll2) both run the pad in "relative" mode, and while that facilitates a simpler driver because the pad does most of the work, it is very limiting of what you can do.