This study examined how contextual factors influence support providers’ motivations and message provision. Participants (N = 602) provided supportive messages in response to support-seeking posts sent either publicly or privately through either Facebook or an online support group. Findings revealed that providers’ motivations and message provision varied as a function of the channel and privacy of communication. Moderated mediation analyses showed that privacy moderated the indirect effect of channel on verbal person-centered message provision through approach motivation. This project advances extant understanding regarding direct and indirect effects of contextual factors and motivations on the quality of supportive messages people produce.