The Mighty Mouse's scroll ball is designed to let people scroll vertically, horizontally and even diagonally, the company said Tuesday. The scroll feature is suitable for viewing Web pages and photographs, as well as editing video and creating music, the company said.
Apple notes also that while the device has multibutton functionality, it can also work as a single-button mouse.
Two of the buttons are actually programmable touch sensors. People can click the upper right or left side of the mouse to access features like menus in Mac OS X and other applications.

Source: CNET News