Scrollbars serve three purposes: - they offer an affordance (a control) for moving a viewport. - they offer the indication that there is more to see than just

Scrollbars serve three purposes: - they offer an affordance (a control) for moving a viewport. - they offer the indication that there is more to see than just the current viewport - they can offer an indication of where your viewport is in the overall data window, and optionally what percentage of the overall data window is covered by your current viewport.