Facebook has become one of the most prominent tools for social networking over the last few years. Since its establishing in 2004, more and more players have made use of it: not just ordinary users willing to find their old friends and to get back into contact with them, but also, for example, more and more players from the cultural scene. These latter ones include cultural institutions willing to experiment with new ways of getting in touch with their traditional audiences but also willing to attract new audiences (like a younger audience, who is supposed to be more present on such social media); artists, who use it to create a community to share information, to promote their own creations but, more recently, also to collaborate on common project; and finally also libraries. This paper intends to explore the use of Facebook in university libraries by making an empirical analysis of current practices. In doing so, the paper builds on the knowledge gained in a previous study on the way in which Flemish cultural institutions make use of the possibilities offered by social media to communicate with their audiences and to promote themselves [2]. The analysis on current uses we performed will help us sample existing practices and help us derive some general ideas for future best practices. And this will help libraries to better profile themselves and communicate better with their old and new audiences.