Mobile phones play a major role in teenager sociability. Our analyses are based on ethnographic observations focused on their uses in school. This particular social context which is intrinsically a collective one allows us to go beyond the statement that mobile phone is only an interpersonal communication tool. That leads us to expose shared uses and to explore young people’s ways of being together. In this normative context what teenagers do with their cell phones reveals their relationships to rules and limits and their relationships within an adult world which is not limited to family.