Principle-based pedagogical and technological designs were used to support knowledge building in a grade 5-6 class. Pedagogical designs focused on collective responsibility for knowledge advancement. Technological designs focused on provision of a public space for generating and continually improving ideas with (a) social-network-analysis tools to analyze and support community processes, and (b) vocabulary-analyzer and semantic- analysis tools to analyze and support conceptual growth. The tools were used by teachers, students, and researchers. Multi-level content analyses revealed patterns of reflective and adaptive use of the technology to support sustained knowledge building.