Collaboration is often a necessity in order to reach one''s goals in society, organizations, or among individuals. Collaborative Virtual Environments (CVEs) can be used as a medium supporting interaction between people. By allowing real-time co-work with graphical representations, they offer new possibilities to facilitate collaboration. Yet, while the use of CVEs is continuously increasing, there is still little research on understanding the consequences of using them as a social medium. Based on five experimental studies, users'' experiences and their performance were comparatively evaluated for different CVE technologies. It was found that although immersive technologies provided greater presence, effectiveness varied more with the tasks than with the technology used. The symmetry or asymmetry in the distributed settings was also found to have a major impact on effectiveness. By focusing on social interaction, interaction via technology and problem solving separately, small sequences of successes and failures during collaboration were analyzed, and a framework for usability evaluation for CVEs developed. The results also support selection of different types of CVE.