The design of hypermedia documents poses specific problems to which it is difficult to transpose the solutions usually applied to the design of structured documents (technical documents, for example) or non-hypertextual multimedia documents (books, films) and to the design of computer applications.
Non-linearity
The non-linearity of reading made possible by navigation means that the designer must anticipate, organize and even control the freedom of exploration he offers the reader. Too much freedom leads to a phenomenon known as "disorientation": very quickly, the reader no longer knows where he or she is in the information space being explored. Conversely, a navigation structure that is too rigid (e.g. mainly hierarchical) leads to the loss of the main benefit of hypertextual structure: the sharing of information between different reading situations.
Human factors
In the World Wide Web, many human and sociological factors play a major role: for example, very fast browsing means that the visual presentation of pages must make the strong points of their content immediately perceptible.
Communication-centric design
Unlike computer applications, whose design is usually highly data-driven, the design of hypermedia documents must be driven by the constraints of human communication (see humanities and social sciences) and, in any case, reader-centric.
Multimedia aspects
Graphic and multimedia aspects are paramount. They require multi-disciplinary design teams capable of taking into account cognitive and aesthetic constraints as well as those of computer origin.
Specificity of the Web, CD-ROMs, technical documentation
A hypermedia document must be designed specifically for its intended use, taking into account the technical constraints of the distribution medium used. A hypermedia document relating to technical documentation will have a navigation structure very closely linked to the task or object it describes; on the other hand, the structure of a CD-Rom for the general public will be more the result of creative work in which the rhetorical structure is predominant; finally, the Web, seen as an information space, supports much simpler, quasi-standardized navigation structures. What's more, the Web is also a space of freedom and "everyone-to-everyone" communication, in which structures emerge from user interaction as much, if not more, than they result from voluntary construction.