Why Do Christian Churches Build Congregations Online? examines the different ways that Christian churches and denominations perceive and use digital media in their external work. This is explored through three different case studies, with dissimilar approaches to digital media, to understand the prerequisites and conditions for media usage from a religious institutional perspective. The case studies included are as follows:The Charismatic movement (with Pentecostal origin)The Church of SwedenThe Laestadian movementThese cases range from a positive and outgoing attitude toward digital media to a hesitant and reluctant approach. The highly secularized and digitally permeated Swedish society gives the context in which the religious institutions must relate and understand themselves in relation to. From a mediatization approach, the national context limits and sets presumptions for the negotiating process. This volume provides an understanding of the relationship between external (societal) and internal factors (such as theology and historical origin). This book will also broaden the understanding of the field of "digital religion" and emphasize the need to discuss contemporary religion in terms of "religion in a digital age".