Introduction

Traditionally information retrieval systems and services have been used by a select few, especially those engaged in knowledge-intensive professions and related activities, such as education and research, law and medicine. However, with the proliferation of web, social networking and mobile technologies, far more people than just those in knowledge-intensive professions now retrieve information. Every time we search for a specific message in our e-mail box, or look for information on the web, in a digital library or on a database of some kind, we use an information retrieval tool like a search engine, which allows us to discover, access, use and share information.

Although use of information retrieval tools has proliferated over the past two decades since the advent and proliferation of web and digital libraries, an information retrieval research community and industry has existed for nearly five decades, engaged in building tools and techniques ‘to improve the process of finding information not only on the web, but also within a single computer (“desktop search”) or a set of computers (“enterprise search”), as well as within very large databases, such as libraries (“database search”). Further, information retrieval techniques have been used to identify key links within, for example, legal records, genomics data, and spam’ (Rowe et al., 2010, 19). Nowadays many researchers prefer to use the term information access instead of information retrieval. Information access includes all the typical information retrieval processes and activities ranging from content and data selection, processing and indexing, to search and retrieval, and use of information and data by users in order to meet their information requirements (Chowdhury and Foo, 2012, 47).

Nowadays we conduct billions of searches every day to find information on the web, library catalogues and databases, digital libraries, institutional repositories, ebooks, e-journals, and so on. For example, Google handled 1.2 trillion searches in 2012 (Google, 2013). Behind every search there is a search engine that collects, processes and manages information from a variety of information sources in order to give us access to the information that we seek. In order to keep pace with the rapidly growing volume and variety of information on the web, digital libraries, databases and information retrieval systems have to work constantly behind the scenes in order to collect, organize and manage information in a manner that facilitates easy access and retrieval.