The interface should be designed so that experienced users don't think of the interaction as reading, they should think of it as exploring; they aren't using a computer so much as visiting a space.

To accomplish this, as the exploration progresses, some previous context must vanish from the screen since the screen is finite, but that context must be easily refindable with a simple graphical memory of a trail through the information space. Explorers should never get so lost that they have no idea where they came in.

To achieve this:

Displayed objects should have a static and easily perceptible position (subsequent visits should aid recall of previously visited locales, this is impossible if the displayed location always varies).
Displayed objects should have distinctive shapes, colors, and decorations for the explorer to use as unconscious landmarks.
The explorer's immediately previous context should never vanish utterly.
The system should remember typical trails so that it can prompt explorers.
More experienced users should be able to create distinctive icons representing interesting locales in the space that they can jump to immediately without having to walk there.

The following stages of information organization apply equally well to the structure of paper books, computer programs, websites, desktops, directories, or pages. (Those pages may be pictures, website lists, or anything else.)

Stage I   A linear list of text tags, names, or items.
 
Stage II   A linear list with certain items highlighted with different fonts, sizes, and colors.
 
Stage III   A hierarchical linear textual list with varying fonts, sizes, and colors.
 
Stage IV   A two-dimensional hierarchical textual array with arrows, implicit containment based on height and parenthood, and varying fonts, sizes, and colors.
 
Stage V   A two-dimensional hierarchical array with arrows plus distinctive and appropriate (and so memorable) icons attached to certain items.
 
Stage VI   A two-dimensional graphical space with various locales marked as containing textual items. Locales should highlight themselves as the explorer moves over them. This lets the explorer be sure of which locale is being selected at present and it subliminally suggests that the system is paying attention to everything the explorer does.
 
Stage VII   A three-dimensional space with sounds and other highlights keyed to various locales. Various locales have hidden spaces that, once entered, obscure much of the complexity of the larger space. The interface has now become an interactive map to a Space.

Almost all of computing, and essentially all of the rest of the world (tables of contents in books, for example), is still, at best, somewhere between Stage I and Stage III.

To jump to at least Stage VI, the system needs to add as many orthogonal dimensions of highlighting (or landmarking) to the display as possible without it getting too crowded and unmanageable. The user should never be in much doubt about where things are in relation to other things.

One way to produce efficient and comfortable navigation might be to provide many redundant navigation aids available on demand to the user. No matter how many navigational aids there are though, the single most important property that they all must share is that their interface properties (their appearance, their sounds, their animations, whatever) must change depending on the user's location and (perhaps) context---and they must change in a regular and consistent fashion.

For example, if a landmark casts a shadow in a certain place, then that same place must be shadowed when viewed from elsewhere. To be considered a space and not a mere assemblage, entities within the assemblage must have constancy with respect to certain fixed and easily learned rules. Those rules need not be the rules we're used to in the real world, but they must exist and must be easy to learn else the assemblage cannot become a space in the user's mind.

Landmarks: There must be visual (and perhaps aural) landmarks in the space. These landmarks could be completely arbitrary or they could be related in some way to some of the pages they're near to. Initially they might simply be different images scattered at random over the space.

It might be good for these images to be computer-generated so that they can change as the pages they're near to changes, however they can't change so fast that the user loses a sense of continuity with the landmarks, or they will cease to be landmarks.

Landmarks may also be more global than the equivalent of statues in a square or clock towers or cathedrals: they can be the equivalent of rivers or coastlines or mountain ranges; anything that vividly distinguishes its environs from the rest of the space is a landmark.
 
Maps: There must be at least one, possibly many, overviews of all of the space available. The user's present location and perhaps several past locations should be marked or markable on such overviews.
 
Graffiti: Users should be able to adorn their spaces with graffiti on the space itself. Graffiti could be page annotations, random jottings, or could serve as landmarks in their own right.
 
Scale: Different portions of the space representing related pages should be separated from other portions with lots of empty space to let users mentally categorize portions and so aid orientation by reducing the demands placed on human memory.
 
Past Trails: Previous trails through the space should be available to the user. Users may remember pages by the sequence of visits to other pages in different clusters.
 
Teleport Buttons: In a vast space with pages scattered in different clusters the user may initially get to any one cluster by traveling over the space, but once there if there is a page with multiple locations the user should be able to click on the page's teleport button and be transported to another cluster. Repeating this process cycles the user through all the clusters that particular page appears in. After exhausting those clusters the user can choose some other page in the current cluster and click on its teleport button, and so on.

Teleporting should always be accompanied by some kind of animation to give a feeling of movement and direction so that landmarks and scale aren't lost in the process. The user should always be given visual and audible hints during the teleport of the origin and the destination, with origin hints decreasing and destination hints increasing during the teleport. Teleports should never be instantaneous.