Features Missing in Current Web Browsers (as of 1995)

Here is a list of navigation support mechanisms that have been successful in earlier hypertext systems but are not found in current WWW browsers:

Search (a real search, that is!)
Overview diagram (global and local)
Guided tours (paths)
Tabletops (allowing some hypertext nodes to be seen simultaneously with others that they comment on; useful for educational hypertext)
Fat links (open many destination nodes at once)
Parameterized backtrack
Visual cache
Flying through the information space (and other ways of rapidly visualizing the main parts of the space)
Link inheritance and clustering
Time-dependent notation (breadcrumbs do age in current systems)
Visual effects to emphasize navigational dimensions
Pop-up links (visible in a spring-loaded mode without leaving the current page).
Multi-lingual text-representation (as done in, e.g., Hyper-G - now renamed HyperWave)
Posting relevance ratings with hypertext anchors (e.g., relevance from search or from community-based interest computation)
Filtering of anchors

For more info about these features, see the navigation chapter in my book Multimedia and Hypertext: The Internet and Beyond.