“Open-source is becoming an increasingly popular software development method. This paper reports a usability study of the open-source Greenstone Digital Library collection-building software. The problems highlighted by the study are analysed to identify their likely source within the social context of Greenstone’s development environment. We discuss how characteristics of open-source software development influence the usability of resulting software products. ” (David M. Nichols, Kirsten Thomson and Stuart A. Yeates – Department of Computer Science, University of Waikato, Hamilton, New Zealand)