Several studies on youth and social networks have generally revealed extensive usage of these Internet services, widespread access from almost any location and the special importance that the youth attach to these services in building their social relations. This article presents part of the analyses and results from a research questionnaire on «Scenarios, digital technologies and youth in Andalusia», administered to a population of 1,487 youth between the ages of 13 and 19. The discussion on young Andalusians and social networks revolves around the structure and configuration of their profiles, intended uses and the privacy and security involved. The results reveal a population with nearly unlimited access to social networks and with very little adult monitoring; moreover, those connecting are younger than the legal minimum age defined by the Internet services themselves. The motivations of Andalusian youth for using social networks fall into three areas. The first two, social and psychological/affective motivations, are also commonly found in other studies; the third refers to the need to use social networks in matters concerning everyday life. This paper suggests certain new aspects in its conclusions in order to explain the nature and meaning of the practices of Andalusian youth in social networks.