To understand how bullying is represented within social media, the characteristics of hashtags associated with public mentions of bullying on Twitter between January 1, 2012 and December 31, 2012 are explored in this study. The most frequently used 500 hashtags among the 552,831 distinct hashtags used with the keywords "bully," "bullied," and "bullying" were identified and organized into eight categories. Hashtag features, including the number of tweets and retweets in which the hashtag appeared, the number of unique authors who used the hashtag, and the numbers of URLs, hashtags, and user mentions were found to be associated with hashtag category membership. Differences in the daily usage of hashtags used with bullying keywords were also identified. The differences show that bullying has both an immediate, large scale influence as well as a more every day presence. Benefits of using social media for studying bullying and cyberbullying are discussed.