During the first COVID-19 wave, we conducted a Zoom and WhatsApp digital group intervention that promoted community-dwelling seniors’ mental health. A total of 82 community-dwelling adults participated in this intervention. Based on the media richness theory (MRT) and the affordances approach, we used netnography to explore how group moderators and technical support team members (n = 9), but not the seniors themselves, perceived the ways Zoom and WhatsApp technological affordances/constraints matched intervention tasks and increased intervention performance. We identified four Zoom and WhatsApp affordances: temporality, interactivity, multimediality, and portability. Empirically, our findings represent a first step in creating a conceptual framework for analyzing digital intervention performances that addresses users’ perceptions of technologies and intervention goals. Theoretically, our synergic analysis of MRT and the affordances approach offers a cohesive framework that shifts from a focus on users’ interactions with one type of media to their interactions with all media that are used in attaining intervention goals.