Highly engaged online communities can be characterized in terms of level of user activity and the valence of those activities. Positively-valenced communities engage in co-construction through supportive, uplifting interactions, while negatively-valenced communities engage in co-destruction through shared animosity towards outside individuals and groups. Both types of engagement offer prosocial benefits to community members, but this benefit is achieved through antisocial means in co-destructive communities. This study examines the features of one positively-valenced and one negatively-valenced subreddit community to determine if the same engagement factors drive participation in each, and whether these factors may be influenced to promote positive, rather than negative engagement.