Modern user interface paradigms depend on direct manipulation, rapid response and immediate semantic feedback. Up until the early 80s response time was a recognised problem, but with the advent of personal computing and graphical interfaces, user interface designers have often assumed that machines will be fast enough. Response delays were no longer an interesting problem - ever faster computers would make the problem go away. Even if we imagine that network capacity could overtake growth in usage, we are ultimately faced with the fundamental limitations of the speed of light.
Delays are here to stay.
Hypermedia Usability held at the Open University in 1996, and the mass of recent work on user interfaces and CSCW for the web .