Virtual teams and their leaders are key players in global organisations. Using teams of workers dispersed temporally and geographically has changed the way people work in groups and has redefined the nature of teamwork. Emergent leadership issues in computer-mediated communication are vital today because of the increasing prevalence of the virtual organisation, the flattening of organisational structures and the corresponding interest in managing virtual groups and teams. This paper examines the communication behaviours of participants in two different case studies to determine if number, length and content of messages are sufficient criteria to identify emergent leaders in asynchronous and synchronous environments. The methodology used can be embedded in collaborative virtual environments as technology for detecting potential leaders.