The website Reddit has received scant attention from educational researchers despite the presence of numerous teaching-related subreddits that host thousands of threaded conversations. The purpose of this study was to provide an initial comparison of discussions occurring in several different affinity spaces on Reddit. Because of the lack of relevant prior research, there was no baseline for what to expect in Reddit discussions, so all posts and responses in four different teaching-related subreddits over the course of a full year were analyzed to answer three research questions: How much did individuals contribute to different subreddits? What content interactions occurred in different subreddits? What social interactions occurred in different subreddits? Comparative quantitative analysis revealed substantial differences among the subreddits in terms of levels of voting and network characteristics. Results suggest that Reddit hosts diverse spaces that could present benefits and challenges for educators. These findings are addressed in relation to the extant literature and implications for educational practice and future research.