In this paper, a specific group awareness approach for CSCL settings, namely knowledge awareness, is presented. We classify knowledge awareness in relation to already well-established concepts like shared mental models, common ground, and transactive memory system in order to provide a comprehensive definition of this approach. The functionality of knowledge awareness tools aiming at fostering knowledge awareness is conceptualized in a cyclical model. Three application scenarios are presented to illustrate how knowledge awareness tools work in three different tasks. All these knowledge awareness tools have been found to be effective, that is all tools could foster knowledge awareness and led to increased learning performance.