In the Brand Intelligence framework, online communities—Module 3—connect existing and potential users. Their core purpose is to give brands ownership of the pre- and post-purchase stages of the user decision journey, while accumulating users and credible content to attract potential users from the public domain and generating rich behavioral data to support algorithm-driven marketing and continuous experience optimization. As demonstrated in the NIO case, a well-cultivated brand community can transform customers into ambassadors, collaborators, and loyal advocates. This chapter examines the strategic role of online communities within the broader private-domain ecosystem. It covers key elements of community design, including network structure, incentive mechanisms, and integration with other modules. It also outlines strategies to unlock monetary, social, and data value—while preserving the community’s organic and democratic nature—and concludes with an in-depth online supplemental case study of NIO’s community-driven model. Core Concepts: Online community; Content platform; Incentive mechanisms; Brand ambassadors; Behavioral analytics; Sentiment analysis; Innovation hub; Crowdsourced marketing; Focus group; Community-as-a-service; Democratic governance.