Metaculus is a community forecasting platform that delivers ML-optimized collective intelligence on topics of global importance. The platform brings together a global reasoning community, and keeps score for these thousands of forecasters via explicit, standardized track records. Built on data, it generates scalable ensemble forecasts while delivering consistent feedback on the quality of the reasoning and analysis of its participants. The collective intelligence generated by Metaculus connects rigorous modeling and the scientific method to complex real-world challenges, thereby improving decision-making and fostering transparency and accountability in the public domain. Its open access ensemble forecasts provide a sense-making utility for hundreds of thousands of readers, and are trusted by the scientific community, government agencies, effective charities, and the Fortune 500.