This book constitutes the refereed proceedings of the Third International Workshop on Distributed Communities on the Web, DCW 2000, held in Quebec City, Canada, in June 2000. The 19 revised full papers presented together with 2 keynote contributions were carefully reviewed and selected from 30 submissions. The book presents topical sections on collaboration in communities, business communities, managing communities, communication and communities, intentionality, and mobile agents for community support.