This study analyzes the influence of avatars on social presence, interpersonal trust, perceived communication quality, nonverbal behavior, and visual attention in Net-based collaborations using a comparative approach. A real-time communication window including a special avatar interface was integrated into a shared collaborative workspace. Communication modes under investigation were text chat, audio, audio-video, and avatar. Significant differences were found between text chat and all other communication modalities in perceived intimateness, co-presence, and emotionally-based trust. Microanalyses of nonverbal activity and visual attention point to similarities between video and avatar modes, both showing higher levels of exposure to the virtual other and visual attention, in particular in the initial phase of interaction as compared to text and audio.Technologies for computer-mediated communication (CMC) and collaboration are advancing rapidly. Shared workspaces and collaborative virtual environments allow for real-time information interchange and the synchronization of distributed working efforts over large distances. However, real-time access to information is only one determinant of efficient Net-based collaboration. Even more relevant in individual, societal, and economical respects could be the possibility to substitute face-to-face (FtF) meetings, which despite high costs are still the preferred interactional setting (Walther & Parks, 2002) when it comes to more complex communication tasks involving socioemotional aspects. Gates (1999) formulates the vision of global collaboration as follows.What do people do at work? They go to meetings. How do we deal with meetings? What is it about sitting face to face that we need to capture? We need software that makes it possible to hold a meeting with distributed