Have you ever visited a website and found you have no idea where you are or what the system is expecting you to do next? It\u2019s not that the site isn\u2019t designed well or doesn\u2019t work as promised. It\u2019s that it just doesn\u2019t make sense to you. My school-age netizen daughters summarize this experience with a resounding "Duuhhh!" In my mind, this experience isn\u2019t necessarily a failure of logic or navigation. The problem is more fundamental to the human experience with systems. It\u2019s a problem of metaphor.Metaphor is a familiar concept in literature. Merriam-Webster\u2019s Collegiate Dictionary defines metaphor as "a figure of speech in which a word or phrase literally denoting one kind of object or idea is used in place of another to suggest a likeness or analogy between them." In Ernest Hemingway\u2019s novel A Farewell to Arms, he uses rain as a metaphor to symbolize the pain and sadness his characters feel as they confront the horrors of war. When building systems, designers often portray the coded worlds they create using metaphor so that they are easily understood and quickly accepted by users.So what does metaphor have to do with technology? Well, if you think of metaphor as the intuitive dimension of good user interface design you might find that your users are happier and more comfortable. Good webpage designers know how to choose aesthetically pleasing combinations of graphics, fonts and colors. Capable software engineers know how to create screens and transactions that function properly. An effective metaphor makes a site or system intuitively obvious to the new user by providing comfortable and familiar surroundings that help users quickly absorb the content of a site or adapt to the rules of a system. Take the shopping cart used in online stores, which helps ground users by providing a brick-and-mortar object for them to relate to. An ineffective metaphor makes the system more difficult and less intuitive to understand. It\u2019s possible to design visually attractive systems that function correctly but still confuse and disappoint users. One example of an effective metaphor from my experience involves the creation of a system for a global team of air filtration scientists at a company I used to work for. These users were already looking for a way to catalog their knowledge and exchange new ideas on a daily basis. Because of the academic nature of their work, they wanted a library for their research and reference work that team members around the world could easily access. To meet that requirement, I created a Lotus Notes library database that was customized with meta-data fields that allowed users to search and index their work in ways they were accustomed to. This new virtual library became a metaphor for the physical libraries they used in their individual sites. The group was also accustomed to regularly communicating with their scientific colleagues over the Internet. To meet this need for the internal community, I chose a Lotus Notes discussion forum that mimicked the Usenet groups the team members were familiar with. Finally, I integrated the forum and library so that they were easy to use together as a tool for daily collaboration.I worked closely with the team leader in designing the site, and the leader made it clear from the outset that this tool was the primary way in which he expected the team to work together. The tasks users were required to perform\u2014checking technical documents in and out, filing research reports, asking and answering technical questions\u2014were natural to them and easier to do electronically than on paper. The system itself, because it incorporated so much interface design input from the team leader, was intuitive to the team members and required little or no training. Finally, the team leader recognized team members for the contributions to the library and the forum, creating a peer reward mechanism in the system itself. In just a few weeks, the team was conducting virtually all of its work in the new system.This example showcases the elements of a good metaphor. I created a world that was familiar and credible to the user team. Users recognized activities the system required them to do and found them easy to perform. The system logic matched the users\u2019 intuition with no trapdoors or hidden passages. Organizational values, including reward systems, were faithfully represented in the system. Users even found the vocabulary (meta-data) familiar and used properly.An example of an ineffective metaphor involved a situation with a similar system at the same company. Scientists in another group working on proprietary technology were also accustomed to working with their colleagues around the world and regularly sharing their research reports and technology development. Given the success of the earlier Notes library and forum system, I decided to go about this project in the same way. However, this set of scientists was used to working together on paper in a very strict set of information security protocols. They were not accustomed to working via the Internet because of the perceived risk of sharing their information in public, so the metaphor that worked for the first team didn\u2019t work for the second. In building the system for this team, I failed to include the key elements of the team\u2019s security protocols in the design. Consequently, the early users of the system felt that they were doing something wrong by violating information security measures they considered critical in safeguarding the information they were handling. Because the system I presented them with didn\u2019t seem credible and supportive of their work and their values, the early adopters never generated the momentum that would draw other team members to the system, and the system was ultimately shelved. The system in this case was better constructed than in the first example, but the users didn\u2019t feel right using it.Despite the failure in my example, an ineffective metaphor won\u2019t always kill a project. In many cases, you can customize software to make it more acceptable to users, and some systems are capable of a high degree of personalization that makes the system easy to tailor to individual users. Training can also help users understand a difficult system metaphor. All of these techniques, however, require more time and money to implement, and this higher investment can be avoided by choosing the proper metaphor from the beginning.The use of metaphor is a powerful way to relate new concepts to users. If you choose one that helps your customers see your product or service in a familiar and sensible way, you have a good head start on acceptance of your brainchild. Even the most creative metaphor isn\u2019t a cure-all, though. Designers still have to do the fundamentals right. A familiar, comfy cyberworld won\u2019t make up for bad interface design or faulty system logic. The right combination of a solid business model, good system design and a carefully crafted metaphor will have users right where you want them: attentive, productive and delighted. Instead of denouncing you with "Duuhhh," they\u2019ll sing your praises with "Aaahhh!"