Based on a qualitative comparative study across four domains, this paper explores how the use and perceived usefulness of scholarly mailing lists is related to primary search methods, collaboration patterns, loci of critical information, physical proximity of like-minded colleagues, field size, the desirability of sharing information in public or semi-public discussion fora, relevance criteria, the degree of scatter within a field, and book versus article orientation. The findings show the differential role of formal and informal computer-mediated communication across fields. Environmental biologists and nursing scientists saw little value in mailing lists for research purposes. They relied on their local collaborators as sources of support and advice. Historians and literature and cultural studies scholars experienced mailing lists as helpful in monitoring literature and progress of the field.