The Catholic Church has been moving into a new phase, one where its congregation can choose to meet and practice elements of their own version of their faith on online forums. This new form of congregating allows for an individualised faith to manifest itself outside of the usual church authority structures. Online Catholic Communities provides insight into how religious and non-religious internet forum users interact and form groups during interactions; it also discusses the transformation of religious authority and its emanations in these digital contexts. Using the top three online forums used by Polish Catholics as a case study, this project explores the formation of these online communities. It then looks at the alternative authority structures that emerge online and how these lead to an individualised form of religious engagement that can develop independently of mainstream doctrine. Through highlighting how religious discourse in Poland is appropriated and creatively modified by users in fulfilling their own spiritual needs, this work reveals the constant interplay between online and offline religious contexts. This monograph includes cutting edge research on online expressions of religious community, authority and individualisation and as such will be of keen interest to scholars of religious studies and the sociology of religion, as well as communication studies.