Abstract
In this paper, I preliminarily characterize and evaluate two variants of a pattern of collective argumentative criticism in online political discussion forums available through Google Groups. In the first variant-horizontal criticism-a group of arguers jointly objects to distinct elements of complex argumentation put forward by their opponent. In the second variant-vertical criticism-a group of arguers acts in sequence by deepening the previously voiced criticisms against one element of their opponent's argumentation. Such collective criticism of arguments is to a certain extent the reverse of a pattern of joint production of arguments, or a “tag-team argument, “identified by analysts of argument in small face-to-face groups. I argue that collective criticism can enhance public scrutiny of opinions expressed in informal deliberation, yet it can also lead to inconclusive argumentative discussions.