Open Source Observer (OSO) is the impact measurement platform for the open source community. The OSO data lake works as a central place where anyone can share, explore, discover, and experiment with data to evaluate the impact of open-source projects and ecosystems. OSO empowers the next generation of impact data engineers, scientists, and users to learn, collaborate and share their work to build a sustainable public goods future together. With the fast-growing community, some of the most used open-source data sets and tools, and a talented science community exploring the edge of impact measurement, Open Source Observer is at the heart of the public goods revolution.