The article discusses the way pixação (graffiti style of São Paulo city), carried out by young people from marginalized and invisible areas of the city, produces visible senses encrypted against the walls and buildings. The proposal is structured around the following research question: "How do pixadores make senses in the marginalized context of pixação?" Other secondary research questions include: (i) How pixação is socially organized in São Paulo? (ii) Which senses does pixação mean for pixadores? A set of 10 interviews with pixadores (those who do pixação), on-site visits for 8-month period, and media content analysis were carried out, in order to understand its dynamics. The data was analysed through thematic analysis, added field notes and iconographic data as complements of the observations. The data shows that pixação is a clustered communication between the socially "invisible" (individuals or groups suppressed in social scopes), which occurs visibly in urban public areas. In this sense, pixação acts as an urban reference creation device, and, although the activity has different meanings for the pixadores, the pixação in São Paulo has its own mechanisms of organization, communication and memory.