“The “World Café” is a structured conversational process intended to facilitate open and intimate discussion, and link ideas within a larger group to access the “collective intelligence” or collective wisdom in the room. […] the focus is on exploring and innovating on themes rather than on problem-solving.The format is principally designed as a forum for creative or open thinking and is not suited to scenarios where there is a predetermined answer or solution.” (Wikipedia)
More detailed information about the facilitation method and its principles, see here.