Wiki is radically simple. A few hundred lines of cgi script combined with the emergent behavior of the internet community has produced results which continue to delight and amaze. But simple replication of the site often leads to disappointment. In this talk Ward Cunningham explores both the delights and challenges of growing large wiki. He then shows how autonomous exchanges between wiki sites can solve nagging problems in monolithic implementations and create a new medium that will be a lot of fun for everyone.