We describe the use of ethnomethodologically-informed ethnography as a means of informing the requirements elicitation, design, development and evaluation of digital libraries. We present the case for the contribution of such studies to the development of digital library technology to support the practices of information-searching. This is illustrated by a particular study of the help desk at a university library, examining the implications it has for designing appropriate functionality for a digital library. This requires us to address the problems of using ethnographic data in systems design.