Social network sites and digital activism allow participants to engage in social movements with lower participation costs and organizing costs, yet with higher risks. Thus, the traditional role of Social Movement Organizations (SMOs) in providing selective incentives is challenged. A comprehensive understanding of social movement, especially digital activism, can only be achieved by recognizing both SMOs’ and individual activists’ contributions. To compare their online roles and abilities with each other, I focused on the Black Lives Matter movement as a case study and leveraged 23.7 million tweets from 5.5 million users. SMOs and individual activists are classified at scale using the RoBERTa model with Lamb optimizer to mitigate sampling bias. I concluded that activists and SMOs have similar online behaviors in overall influences and their contribution to the social movement’s continuity and long-term viability. However, SMOs still dominate in stimulating conversation among new audiences compared to activists and other types of accounts in the online setting.