Visual metaphors based on familiar objects and activities often serve as the design theme for software interfaces. The Windows and Mac operating systems both use the metaphor of a desktop for their user interfaces. Interaction with their file systems involves objects that are common in the workplace, including file cabinets, folders and trash cans. A good visual metaphor in this context provides the user with an immediate understanding of how the software works based on existing knowledge of something already familiar, resulting in a reduced learning curve. Once you've learned how to use the software, however, the metaphor rarely continues to matter. From that point on, all that matter are the merits of the interface for effective and efficient use. The business intelligence (BI) dashboard is a striking example of software that uses a visual metaphor. The dashboard of a car, given its familiarity, is a fitting visual design model for software that displays the information you must easily and efficiently monitor to do your job and achieve your objectives. Most meters, gauges and traffic lights that exist in virtually every dashboard product can be understood with little instruction. That's the advantage - the only advantage - of the dashboard metaphor. The joy of being greeted by those cute display widgets on the first day that you use your dashboard, however, wears off after a few days, and what you're left with is a dashboard filled with gadgets that are just plain annoying and a poor use of valuable screen space. I think most software vendors have taken the dashboard metaphor much too far. (Stephen Few)