An unconference is a facilitated, participant-driven conference centered around a theme or purpose. The term "unconference" has been applied, or self-applied, to a wide range of gatherings that try to avoid one or more aspects of a conventional conference, such as high fees and sponsored presentations. For example, in 2006, CNNMoney applied the term to diverse events including BarCamp, Bloggercon, and Mashup Camp. The term is primarily used in the geek community. There are parallels with science-fiction fandom, in which a low-key convention with less structure is called a Relaxacon.
In his 1997 book Open Space Technology, Harrison Owen discussed many of the techniques now associated with the modern unconference, although his book does not use the term "unconference."
The term unconference first appeared in an announcement for the annual XML developers conference in 1998. More recently, the term was used by Lenn Pryor when discussing BloggerCon and was popularized by Dave Winer, the organizer of BloggerCon, in an April 2004 writeup.
The 2003 FooCamp gave wide publicity to the particular unconference model where "there is no agenda until .. the attendees made one up." 
Styles of facilitation
An unconference can be conducted using a number of different facilitation styles. Some of these are:
- Appreciative Inquiry
- Barcamp and its cousin BIL
- Birds of a Feather
- Code Camp
- The Fishbowl
- Knowledge Cafe
- Lightning Talks
- Open Space Technology
- Speed Geeking
- World Cafe
- ↑ money.cnn.com Why "unconferences" are fun conferences
- ↑ CNN.com When geeks go camping, ideas hatch