Th e subject of this article is the effi ciency of popular justice as the informal mechanism of public safety production on the example of Polish users of facebook.com. Th e investigation was based on the empirical data collected from Polish public discussion groups on the facebook website. Th e qualitative analysis of digital data allowed a presentation of what forms popular justice takes today and what kind of reconceptualisation it undergoes in comparison to its previous forms. Th e theory that backed up the study was the concept of informal institutions which allowed the most important characteristics and their changes to be demonstrated. Th e results show that popular justice is an ineff ective mechanism of public safety production because of its selectivity and the high level of emotions related to judging people, which makes a just judgment impossible.