Abstract In this thesis, I have explored how an online community fosters communication and knowledge sharing in a global company. Based on empirical findings in this study, combined with theoretical aspects and previous research, I aimed to do research in one online community in a global oil service company. I was curious about how an online community, such as The Edge, can foster communication and knowledge sharing among the employees in the Company. My research questions aimed to explore what characterise the use of an online community, how knowledge sharing is facilitated and what impact cultural differences could have on the level of activity in an online forum. Through the sociocultural approach (Clark, 1991;Vygotsky, 1978; Rommetveit, 1979; Wertsch, 1998), the thesis explores how technology as a mediating artefact promotes communication, intersubjectivity, common ground and knowledge sharing. Other theories are used, along with previous research, to illuminate the problem framing of the thesis and the research questions. The study has a qualitative approach, where I conduct a virtual ethnography of the discussion forum in The Edge, and qualitative interviews with four active members of the community. Such a triangulation of the collected data, contributes by enhancing the validity of case study findings. The data analysis is inspired by an interactional and content analysis and interpreted with an abductive approach. The collected data from the discussion forum were first organized in an Excel document, where the approached participants were found. From the transcripts from the interviews, four categories were identified, and the collected data was analysed in light of these. The thematic categories constituted the basis for the theoretical discussion in the thesis. 1. The Edge as an Online Community 2. Learning at Work 3. Collaboration and Knowledge Sharing 4. Linguistic Challenges The data indicates that the level of activity in the online community in the SDS network is high. The employees chose to participate to help others, keep updated on the posted topics because it is expected of them to be active. One may argue that The Edge consists of different communities of practice, with different fields of interest. For the company, as a global business, it is an advantage that the online community allows communication asynchronously, regardless of time and place. The Edge facilitate knowledge sharing with a workload-reducing function, It is a community that stores and obtain knowledge and support both primary and secondary work activities. Multiple learning strategies are used in the SDS network, with indications of allowing both a fix-it-level and a reflection level. Technical questions are structured within primary work tasks, and ideas and suggestions is found within secondary work. Cultural differences consist of linguistic barriers within the community. This may cause complication in the communication and affect the level of activity. Intersubjectivity and a common ground is crucial to achieve knowledge sharing. By succeeding this on this aspect, it might be possible to transfer tacit knowledge to explicit knowledge in the company, as knowledge from the world to knowledge in the head.