This study investigates ways of using key terms to represent and assess community knowledge in an online knowledge building environment. Knowledge Forum – an environment specially designed to support advances in community knowledge – incorporates key-term analytic tools. In the current study these tools were used to determine if key-term measures complement conventional online behavioral measures in assessing community knowledge advances. Discourse rated as more reflective and depth-oriented showed higher percentages of shared key terms and higher frequency use of shared key terms than less reflective, shallower discourse. Limitations and possibilities for using key terms for automated assessment and visual representation of community knowledge are discussed.