People sometimes explicitly announce that they are being sarcastic. The announcement appears to be particularly common in text-based conversations where prosodic cues are more difficult to identify. In certain cases, the tone of a comment is sufficient to determine non-literal meaning. However, what happens in the absence of these features, or when context forces us to explicitly caveat our sarcasm? In this study, we examined Reddit comments from r/AskReddit for the features that are present in comments tagged with "/s", a convention on the platform for users to denote sarcasm. We found that a host of cues which mimic prosody, and other aspects of figures of speech, were inconsistent predictors of announced sarcasm. In contrast, when talking about sociomoral topics such as politics or race, users were more likely to tag their comments with "/s". This suggests that users are more likely to announce sarcasm in text-based conversations where misinterpretation would be socially detrimental.