Abstract: Content has historically been the primary lens used to study the language of online communities. This paper instead focuses on style of communication. While we know that individuals have distinguishable styles, here we ask whether communities have distinguishable styles. Additionally, while prior work has relied on a narrow definition of style, we employ a broad definition involving 262 features to analyze the language style of 9 online communities from 3 social media platforms discussing politics, television and travel. We find that communities indeed have distinct styles. Also, style is an excellent predictor of group membership and is on average better than prediction using content while also being more resilient to reductions in training data.