The evolution of digital technologies has contributed to ordinary citizens' engagement with media culture as a way of expressing themselves in public spaces as part of the so-called phenomenon of 'self-mediation' (Chouliaraki 2010, Perez-Gonzalez 2014). An increasing number of people are participating in producing, consuming, and disseminating media content among like-minded people in pursuit of their individual interests and agendas. In today's networked society, such self-mediated content may contribute to boosting the digital diaspora, facilitating the exploration and negotiation of shared interests among individuals from different lingua-cultural backgrounds, and enabling the formation of communities of affinity. Even though translation plays a vital role in these processes, the translation of self-mediated content and, in particular, the role of translation in the production of such content, is still an under-researched area in translation studies. Against this backdrop, the objective of this PhD thesis is to explain how translation as a process of self-mediation contributes to the establishment of social ties among content creators and their geographically fragmented audiences. Specifically, it examines translated vlogs - i.e. video blogs, a new audiovisual genre that has emerged as a form of self-mediated content in our participatory digital media culture - distributed globally through the YouTube platform. My analysis consists of two different case studies and investigates the translations of vlogs from different genres, i.e. 'beauty vlogs' and 'culture-brokering vlogs'. These genres not only reflect the content creators' own interests, but also deploy different media practices, including translation practices. Among various genres of Korea(n)-based videos, these two specific genres are drawing attention from Korean domestic viewers as well as global viewers. Accordingly, a number of YouTubers who create content in these genres provide translations in order to reach out to the different language constituencies of viewers. This thesis draws on affect theory, primarily the Spinozan-Deleuzian approach, and the framework of sense of community (McMillan and Chavis 1986) in order to explore how the translation of YouTube vlogs contributes to establishing virtual communities of interest built upon shared affinity among people who interact through vlog-mediated communication. I argue that translation is a community-building apparatus - and hence a form of affective labour. In other words, translation may generate and manipulate affect, i.e. a prepersonal and autonomic intensity or power that modulates our bodily capacities to feel and act in certain ways, thereby influencing how viewers react to translated vlogs and communicate with YouTubers and fellow viewers. Ultimately, translation facilitates the formation of transnational communities involving an ongoing, iterative process of mutual engagement among YouTubers and their geographically dispersed viewers and of exchanging emotions and opinions.