Abstract : An empirical research reveals how the users of an intranet relay chat in a company tend to develop personal, anonymous and communitarian relationships in a professional context. These relationships are structured thanks to a plurimodal communication induced by the use of the chat (phone calls, direct meetings, e-mails). In certain cases, chatting can help employees to fight against distress and isolation. The use of nicknames allows a freedom of expression in rupture with the way people usually communicate in firms. The anonymity of the users and the difficulty to legitimate the use of the chat in terms of productivity lead to a lack of trust in the relationships, because the users fear for their professional reputation. In order to restore this trust, they increase the efforts to gather and to check information on the identity of their interlocutors. The organizational context makes easier this restoration of trust relationships.