Introduction

Information retrieval systems are purposeful devices developed to service multiple objectives from locating the current weather conditions to identifying critical evidence for use in complex decision making. Those systems evolved from extracting bibliographic data held in large libraries of references, to retrieving nuggets of information from full-text repositories. However, we tend to think of information retrieval systems simply as generic search systems that respond to a query with a set of results to meet some information need, rather than purposeful applications whose raison d’être is to deliver task-specific information that leads to problem resolution. The early discussions about information retrieval systems implicitly and erroneously equated the concept of task with a user's information need, problem, question or request (e.g. Saracevic et al., 1988; Saracevic and Kantor, 1988a, 1988b; Tague-Sutcliffe, 1992); the exact word used depended on the decade and origin of the work. The task that triggered the need was usually considered peripheral to the research.

The explicit study of task is relatively new in information science. It appeared, for example, as an index term only in the second edition of Case's (2002, 2007) seminal analyses of information needs and seeking research. Its systematic use in information seeking and retrieval research is within the 21st century, a focus that occurred for several reasons, and possibly as a consequence of all of them: