This paper analyzes the role of Internet Discussion Groups (IDGs) in informal academic communication. It examines the claims in the literature that there are general benefits of academic mailing lists and newsgroups for researchers. Different hypotheses relating to potential contact and information benefits are tested with data of a random sample of English and Dutch university researchers within the humanities, the social and natural sciences. The outcomes support hypotheses about a few information effects and, more often, contact benefits of IDGs. Researchers build up weak contacts that make their research more visible and that make them more aware of other researchers’ work. These weak contacts are useful for the reception of new research papers. As a result, IDGs provide access to social capital. However, contrary to what is stated in the literature, the data shows no evidence for expectations about equalizing effects on the general structure of academic communication. IDGs do not reduce inequalities in the opportunities to use informal communication channels.