The paper suggests a new conceptualization of deliberation, namely cumulative deliberation, and makes a critical meta-review of the recent studies of cumulative deliberation made by a group of St.Petersburg scholars in 2019–2021. The concept is based on the idea of tug-of-war-like cumulation of opinion, mostly in online discussions; it aggregates cases of deliberative wins/losses under one umbrella and, i.a., insists that the ‘spiral of silence’ and silent majority theories are individual cases of cumulative deliberation. Our conceptualization allows for closer-to-life interpretations of the dynamics of deliberative online discussions due to a shift in normativity. Instead of demanding a high level of rationality and orientation to consensus from all (or major) discussion participants on social media, the new concept helps add value to micro-acts of deliberation and opinion cumulation, including likes, comments, and shares, whatever emotional, aggressive, or trivial they might be. To illustrate and operationalize the concept, we provide a review of the recent findings of our research group in the area of cumulative opinion formation and cumulative deliberative practices. This allows for grouping the results into four major research areas, which are cumulative patterns of discussion, structural impact of cumulation, relations between cumulation and discourse features, and relations between cumulative patterns and discussion context. We argue that cumulative deliberation may be viewed a dominant practice in polarized political discussions online.