This paper examines gender effects reported in a quasi-experimental implementation of a social dilemma using Facebook profile owners as subjects. By sending personal invitations via Facebook interest groups, we were able to recruit a fairly large number of participants (N = 216) who participated in a “one-shot” variation of the Voluntary Contribution Mechanism (VCM). In addition to participating in the social dilemma, participants provided information about their online profile and their attitude towards Facebook. We observed gender effects on the cooperation style of participants who use Facebook frequently in order to communicate not only with friends and family but also with work colleagues and business acquaintances.