An unconference is a conference where participants collaborate to determine the agenda and sessions. It allows for creative, effective idea exchange in a flexible structure. Unconferences began in 1998 and were popularized in 2004. They typically involve self-organizing discussion groups led by participants on proposed topics. Participants can pre-register online and propose session ideas. Unconferences follow principles like whoever attends is the right audience and they end naturally. They are useful for addressing complex issues with diverse groups and potential conflicts.