The emergence of citizen journalism has prompted the journalism field and scholars to readdress what constitutes journalism and who is a journalist. Citizen journalists have disrupted news-media ecosystems by challenging the veracity and representativeness of information flowing from mainstream news-media newsrooms. However, the controversy related to the desired level of citizen involvement in the news process is a historical debate that began before the citizen-journalism phenomenon. As early as the 1920s, journalist and political commentator Walter Lippman and American philosopher John Dewey debated the role of journalism in democracy, including the extent that the public should participate in the news-gathering and production processes. This questioning of citizen involvement in news reemerged as an issue with the citizen journalism phenomenon around the late 1990s. People with no news-media organizational ties have taken advantage of the convenience and low cost of social computing technologies by publishing their own stories and content. These people are referred to as citizen journalists. Scholars have assessed the quality and credibility of citizen-journalism content, finding that citizen journalists have performed well on several standards of traditional news-content quality. Levels of quality differ dependent upon citizen journalists’ goals and motivations, such as serving the public interest, increasing self-status, or expressing their creative selves. As it is an emerging area of study, unarticulated theoretical boundaries of citizen journalism exist. Citizen-journalism publications emphasize community over conflict, advocacy over objectivity, and interpretation over fact-based reporting. In general, citizen journalists have historically acted when existing news-media journalists were not fully meeting their community’s informational needs. Scholars, however, vary in how they label citizen journalists and how they conceptually and empirically define citizen journalism. For example, researchers have shifted their definitional focus on citizen journalists from one of active agents of democratic change to people who create a piece of news content. The mapping of the citizen-journalism literature revealed four types of citizen journalists based on their levels of editorial control and contribution type: (1) participatory, (2) para, (3) news-media watchdog, and (4) community. Taken together, these concepts describe the breadth of citizen-journalist types. For those of us interested in journalism studies, a more targeted approach in the field of citizen journalism can help us build community around scholarship, understand citizen journalists’ contributions to society and practice, and create a more a stable foundation of knowledge concerning people who create and comment on news content.