I am frequently asked the difference between a Knowledge Cafe and Community of Practice (CoP) as it is not always clear to people.
Etienne Wenger defines a Community of Practice as a group of people who share a concern or a passion for something they do and learn how to do it better as they interact on a regular basis.
A Knowledge Cafe on the other hand is a highly adaptable face to face conversational process that can be used in many different business situations to bring a group of people together to have an open conversation for a specific purpose.
A Cafe can be run as a one-off event, for example to explore the impact of a new technology or as a regular series of events, for example a series of talks/cafes on a specific theme or a variety of different themes.
A Cafe or a series of Cafes does not constitute a CoP. And although a series of Cafes for people with a common interest may appear very CoP like, in reality a CoP will adopt many different ways of interacting rather than just the Cafe format. e.g. less structured conversations, open space technology sessions and on-line discussion forums.
So in summary, the Knowledge Cafe is a powerful conversational tool that can be employed by a CoP but is not the same as a CoP.
I hope this helps.