This study examined how creating a human presence in organizational online communication affects organization-public relationships and publics' favorable behavioral intentions to engage in word-of-mouth (WOM) and dialogic communications. Four hypotheses were tested in the context of Twitter through a 2×2 (presence: human vs. organizational×organization type: nonprofit vs. for-profit) within-subjects design. The results revealed that conversational human voice was perceived to be higher for Twitter pages of organizations with a human presence than for those with an organizational presence. Providing a human presence on social media through the use of social media managers' avatars and names appeared to promote favorable organization-public relationships and positive WOM communication. However, dialogic communication intentions did not significantly differ between organizations incorporating a human presence versus an organizational presence into their Twitter pages. The proposed dynamic role of human presence versus organizational presence adds a new perspective as to how organizations can take better advantage of interpersonal aspects of social media.