Social media is increasingly an essential part of community building. This thesis seeks to understand how the online world mediates marginalized community identity. The examples examined are the respective communities around the Twitter hashtag movements #NotYourAsianSidekick, #CancelColbert, and #SolidarityIsForWhiteWomen. A key focus is the maintenance and patrolling of community boundaries in online spaces. However, this carries its own dangers, such as when community members are excluded because they do not fit a community’s ideals. By comparing and contrasting the events surrounding the aforementioned hashtag movements, I hope to elucidate what coming together as a community in an online space entails.