Think like a search engine, not a command line
We already discussed the evolution of conversational UIs and their connection to the command line and search engines. The user is required to provide the computer with a textual question and in return they get a textual response. However, there is one great differentiator between the user experience of command line versus a search engine. Whereas in a command line the user will receive an error message if they don't use the exact correct format, search engines always return a result, whether it's the answer to your question, something close enough to your question, or even a suggestion for a different search.
In the following example, I asked Google for information about conversational applications, however, I made a mistake in my spelling. Google didn't reply with an error message, but rather tried to fix my request and suggested a possible reply (it does let me know that there are no results for my search).
Figure 3: Think...
