A World Café is a structured conversational process for knowledge sharing in which groups of people discuss a topic at several tables, with individuals switching tables periodically and getting introduced to the previous discussion at their new table by a "table host".
The World Café concept originated at the home of Juanita Brown and David Isaacs in 1995 when a "large circle" conversation became disrupted by rain. In regular events, a café ambience is created in order to facilitate conversation. In some versions, a degree of formality is retained to make sure that everyone gets a chance to speak. Alternatively, the café concept can be taken more literally with everyone potentially talking at once.
As well as speaking and listening, individuals may be encouraged to write down some of their results to inform subsequent people at that table when continuing with this topic. Although pre-defined questions may have been agreed upon at the beginning, outcomes or solutions are not decided in advance.  An underlying assumption of World Café events is that collective discussion can shift people's conceptions and encourage collective action.
World Café events tend to have at least twelve participants, but there is theoretically no upper limit. Groups of about four to six participants sit around tables, together with a "table host", and discuss questions which have been agreed upon at the beginning of the event or defined by the organisers in advance. Each table has a different set of questions belonging to a comprehensive theme. After approximately 20 minutes participants move to a next table where another topic - which ideally is built upon the previous one - is discussed. Discussion results are directly noted down on a makeshift paper table-cloth or a nearby flip chart. The "table host" welcomes new participants and informs them about the results of the previous discussion at the table. Finally, the results of all groups will be reflected on in a common plenum session. Strategies for further actions and opportunities for further cooperation of participants are identified.
In Israel in 2011 an event called 1,000 Tables was hosted in several cities on a single day as part of a series of social justice protests held around that time, and around a thousand people participated.
Another example of a World Café event was one held in Ohio in 2005 with around sixty people, focused around the question "What does ending hunger mean to you?".
In the version developed by David Gurteen (who uses the term "Knowledge Café"), there are no tables, there are no themes or questions for each of the small group discussions, the small group discussions are not led by a facilitator, and no summary is captured for subsequent feedback to the group - the aim is to maximise time spent in conversation and so time spent with one person presenting is minimised.