Search in the lost sense of "query": question formulation in web search queries and its temporal changes

Web search is an information-seeking activity. Often times, this amounts to a user seeking answers to a question. However, queries, which encode user's information need, are typically not expressed as full-length natural language sentences --- in particular, as questions. Rather, they consist of one or more text fragments. As humans become more search-engine-savvy, do natural-language questions still have a role to play in web search? Through a systematic, large-scale study, we find to our surprise that as time goes by, web users are more likely to use questions to express their search intent.