Introduction to the special issue on search intents and diversification

This special issue of the Information Retrieval journal is focused on the topic of query intents and diversification within search engines. Indeed, information retrieval users have diverse search needs, and the level of detail given in the user’s search query can differ widely depending on how clear the underlying information need itself is, the user’s search environment (e.g. input device), and how difficult it is for the user to express the need in the form of a query. For these reasons, many queries are ambiguous and/or underspecified. In light of this, research in accommodating different search intents has received a lot of attention lately. For example, major conferences like SIGIR, WWW and WSDM have begun to see papers on search result diversification, which aims to capture different user needs within one entry-point search result page. This problem was discussed intensively at the ECIR 2011 and WSDM 2012 Diversity in Document Retrieval Workshops. Also, in recent years, the TREC Web (2009–2012) and TREC Blog (2010) tracks have measured the diversity of participating systems in retrieving web pages and blog posts, respectively. Moreover, the recent INTENT tasks at NTCIR-9 and NTCIR-10 tackled not only search result diversification but also the task of mining intents given a query. The aim of this special issue is to highlight the advances and clarify the future goals in the ares of search intents and diversification. In particular, the articles included in this special issue address two areas within this vision, namely the identification of query