With computers, many constructions are metaphoric. For instance, widgets like buttons are metaphors for real buttons. Icons are metaphors for the applications bound to them. This is very well understood, and forms the core of one particular cult of user interface design.
However, we also notice something new with computers that we didn't have before with printed works. Because the computer has the power to enact any informational relationship, the computer can realize the metaphor in a unique way. That is, instead of constructing a metaphor to induce a concept in the audience's imagination, the computer can make the metaphor represent the concept directly.
For instance, VirtualReality is really a metaphor for the underlying data construction of the system (ObjectiveSpace?). However, unlike a mere picture or a plaster model of a town, a VirtualReality enacts the metaphor by allowing the audience to interact within it on a direct level. Thus, the metaphor does not merely allude to another concept, but it becomes the concept itself. The user doesn't feel like she is interacting with the system through the metaphor; she instead feels like she is interacting with the metaphor (the VirtualReality) itself. (SemanticSpace)
A VirtualReality is an extreme example, but this is indeed a common phenomenon. Graphical user interfaces have become not only a metaphor for structured data entry, but now have become first class on their own. Indeed, they have taken on their own morphisms, separate from the forms they were metaphors for earlier. A window manager has no meaning for data entry, but instead it organizes the metaphor?
Computers then not only allow a reification of the conceptual bridge between metaphor and concept, but they make the metaphor the concept itself, inverting the cart and the horse. This is MetaphorInversion.
Navigation systems on the Internet have often undergone MetaphorInversion. While a road map is merely a metaphor for the traffic system, a website map may actually be the structure of the site. Think of it as a map at 1:1 scale. Consider the VisualThesaurus as an example; while the graphic of the relationships between words is a metaphor for the underlying database, the graphic really is the VisualThesaurus. We certainly could not think of a SQL database as being the VisualThesaurus (how visual could that be?). Simply stated, maps of cyberspace exist to change the way we interact with cyberspace, not just the way we look at it.