This case study is the first iteration of a large-scale design-based research project to improve Pepper, an interactive discussion-based learning environment. In this phase, we designed and implemented two social features to scaffold positive learner interactivity behaviors: a "Like" button and linking tool. A mixed-methods approach was used to examine communicative and cognitive characteristics of notes. Additionally, we develop and apply a new metric for cognitive complexity that acknowledges a range of cognitive behavior valuable to a learning community. The findings suggest that the Like and linking functions positively cultivated and sustained interactive behaviors among students, which also led to an increase in the cognitive complexity of student contributions to the online discussion. Suggestions for future iterations of this project are offered.