This chapter reviews the link between religion and the Internet, and considers how this relationship between the online sphere and religions became mobile through the role of communities, social media, and especially mobile applications, looking at how phenomena such as robotics and artificial intelligence could become a very close next step. Scholars investigated whether the Internet would change religious practice and ideology, because of the increase in online communities and the integration of religious practices into the digital sphere. Several characteristics of online religious communities emerge in published studies of different religious confessions. Scholars have focused on the study of identity, authority, and the creation of community because the Internet and mobile technology have influenced religious practices mainly in terms of rethinking those three aspects of religious environments and groups. The chapter shows examples of online trends and practices within Christianity, Islam, Judaism, Buddhism, and Hinduism.