By choosing the concept of a shopping cart, Amazon associated potentially intimidating technology (temporary user database) with a familiar and comfortable object.
Metaphors succeed best when they are concrete, familiar concepts. If used incorrectly, however, metaphors can cause problems. If the wrong metaphor is selected for a concept or if the designer fails to use the comparison properly, the metaphor can cause confusion for the user. (5.5)

The Use of Icons

Icons are one of the four elements (together with windows, pointers, and the mouse) that create a graphical user interface. The conventional--and largely unquestioned--wisdom is that icons are "intuitive" and "user friendly." But do icons actually help users perform tasks and find information, or can they restrict usability?

Since many icons are also accompanied by a caption, is not the image completely redundant? It seems that it would be more efficient to delete the icon and simply use the caption. Edward Teller, a critic who explores the downside of technology, argues that "The [complicating] effect is that while some commands and programs are much clearer as symbols than words, others are resolutely and sometimes inexplicably non-graphic" (Souttar 60). Non-graphic commands and programs result in confusing icons.

Donald Norman, however, argues that users are not supposed to understand the icon the first time they encounter it: "The real trick is to make [the icon] so that when somebody explains it to you, you say ‘ah, I got it,' and you never have to have it explained again" (Souttar 61). So according to Norman, a good icon needs to be explained only once. But who is going to explain to users visiting a web site what each icon means?