Research concerned with a decline of associational involvement has examined whether the use of social networking sites, such as Facebook, may reinvigorate or crowd out involvement in civil society. Yet, previous studies have not systematically investigated possible effects of Facebook use on associational membership. We posit that the effects of Facebook use are twofold: Facebook stimulates associational membership directly through its inherent networking features, and indirectly by compensating for a lack of traditional mobilising factors, such as social trust and internal efficacy. Relying on a probabilistic sample of German participants aged 18-49, our findings show that Facebook users are more likely to be members of voluntary associations and that Facebook use increases the likelihood of associational membership even for individuals with low levels of social trust and internal efficacy. Instead of crowding out offline associational involvement, Facebook use stimulates membership in voluntary associations, thus contributing to the vitality of civil society.
