What types of social processes generate strong online co-production groups? How do these groups evolve to reach peak performance? How does the quality of the products generated by the groups co-vary with the evolution of their social systems over time? The paper analyzes the entire English and French Wikipedia editorial histories, from their inception until 2015, identifying the specific phases through which two different massive online production systems grew. By tracking the emergence of the high contribution group across two different online spaces on a fine-grained level, the paper uncovers their temporal evolutions and impacts on the organization of social systems. Furthermore, the paper reveals how the quality of the content co-evolves with the emergence of the production groups through each growth phase.