A search engine can now respond to users with questions of its own. For example, a search for “truffles” on Amazon returns results, but also suggests “chocolate truffles” and “truffle oil” as alternative searches. Search engines can also interrupt users mid-query with suggestions and even instant answers (e.g., Google Instant). The ideal search engine is a conversational partner that knows when an answer is sufficient and when it needs to ask the user for clarification.
Source: Beyond algorithms: Optimizing the search experience – O’Reilly Media
