Don Norman writes about what he thinks will be the next UI breakthrough:
The new command lines are far more flexible and robust than those of the past. Word order is not critical, often we can use synonyms or even related terms. Spelling accuracy is not even required, for the systems can use its own knowledge to correct spelling errors, or at the least, to suggest spelling variants. Search is never anything I want to do. I don’t want to search — I want to know something. I want an answer engine, not a search engine. The new command line interfaces still have a way to go. They have appeared serendipitously, as system developers slowly expanded the capabilities of search tools. But now it is time to recognize them for what they are and for how much better they could become.
Command line interfaces. Once that was all we had. Then they disappeared, replaced by what we thought was a great advance: GUIs. GUIs were and still are valuable, but they fail to scale to the demands of todays systems. So now command line interfaces are back again, hiding under the name of search. Now you see them, now you dont. Now you see them again. And they will get better and better with time: mark my words, that is my prediction for the future of interfaces.