This study examines the impact of content-based network partitioning and tie definition on social network structures and interpretation for MOOC discussion forums. Using dynamic interrelated post and thread categorization  based on a previously developed natural language model , 817 threads containing 3124 discussion posts from 567 learners in a MOOC on the use of statistics in medicine were characterized as either related to the learning of course content or not. Content-related, non-content, and unpartitioned interaction networks were constructed based on five different tie definitions: Direct Reply, Star, Direct Reply+Star, Limited Copresence, and Total Copresence. Results showed content-related and non-content networks to have distinct characteristics at the network, community, and individual node levels, validating the usefulness of the content/non-content distinction as an analytic tool. Network properties were less sensitive to differences in tie definition with the exception of Total Copresence, which showed distinct characteristics presenting dangers for general use, but usefulness for detecting inflated social status due to "superthread" initiation. Canada.