Detailed analysis of use of the Internet by a cohort of 1,000 persons reveals a wide variety of use profiles, including differences in intensity of use and in browsing practices. In some cases browsing and interpersonal interaction are closely entangled. Since these differences in practices correspond to diverse socio-demographic profiles, we investigate the properties of the system and its modes of appropriation. The Internet profoundly affects relations between reading and writing, both projected onto the same medium, and brings two traditionally separate activities together in an original way, i.e. publication and ordinary conversation in its written form. We show how the type of writing impacts on the way in which social space is constructed and roles and statuses (documents, messages and people) are elaborated during interaction.