Online discussions enable peer-learning by allowing students to communicate ideas on what they have learned in and beyond the classroom. Peer-learning through online discussions is fostered when online discussions are interactive. Interactivity occurs when students refer to and use perspectives shared by peers, and elaborate, respond to, or propose alternative views to those shared by others. Open interactions in online discussions require students to choose whom they communicate with in the discussion forums. This study examines the extent to which the patterns of student-to-student interactions in online discussions resemble student interactions with the same peers in face-to-face settings. Online discussion data were collected in six sections of an introductory IS course over three semesters. Each section's dataset contains data from four online discussions among students, as well as the results of two familiarity surveys administered at the beginning and at the end of the semester. The results of the data analysis suggest a relationship between face-to-face interactions and patterns of online group idea sharing and integration. Understanding the structure and dynamics of interactions in online discussions can provide design guidelines to help overcome inherent familiarity fault-lines in classes, and to improve the extent and quality of peer-learning in online discussions.