DescriptionCrowdsourcing is one of the innovative ways organizations are employing to gather quality ideas from a large group of people. It is used when organizations need to involve a larger group of participants who are collectively invested in the outcome, such as for initiatives with organization-wide implications, that which small group brainstorming cannot sufficiently accomplish. The unpredictability of the process from start to finish however raises questions on the conditions suitable for the large-scale online ideation process that belies the collective action, because it does not seem to parallel that of small group brainstorming. This dissertation documents a mixed-methods case study of a regulatory organization that used enterprise social media for large-scale ideation, with a focus on identifying the enabling conditions for large-scale online ideation, and the factors that may influence the quality of the ideation process. The study found that the process is conditional on having an emergent facilitator, a longer deadline, not having participants pre-selected, and technology that has unique affordances for ideation. The study also found that functional diversity, number of comments, and presence of facilitator are significant predictors for the quality of the ideation process. The study has theoretical and practical implications on ideation, enterprise social media use, collective action, and for organizational communication.