Game users can behave co-operatively or competitively. An experiment was performed to test the hypothesis that a shared social space (SSS) with continuous and 'rich' communication possibilities leads to an increase in forming coalitions. The DOOM game provides a test environment. Two samples of 12 players each were tested playing DOOM: one with the SSS conditions (continuous communication mode, small physical distance among players) and another under the condition of separation during the game (discontinuous communication mode, large physical distance). During a break all players had have the chance to discuss the outcome of the first trial (group process feedback). The SSS conditions led to a significantly increased amount of coalitions between players. Group process feedback also had a positive effect on the extent of coalitions among players. Finally, design recommendations for networked multi-user games are provided.