IICS2004, thefourthworkshoponInnovativeInternetCommunitySystems, s- cessfully dealtwith severaltimely topicsofdistributed systems, the Internetand virtualcommunities.TheworkshopseriescommencedwithIICS2001heldatthe Technical University of Ilmenau. After two more workshops, in Kuhlung ] sborn and Leipzig, this year was the ?rst time that the workshop was held abroad (Guadalajara, Mexico). Due to a broader international environment, the wo- shop this year was organized by the IEEE in cooperation with the Universidad de Guadalajara. Thepapersfromtheconferenceweremainlyfocusedonthreeaspects: syst- orientedproblems, textprocessing, andtheoreticalfoundationofdistributedand Internet systems. The organizers tried to cover the main issues appearing today with the steady growth of the Internet and the Internet communities. Con- quently, the speed and quality-of-service problems of today's Internet protocols, aspects of cooperation and collaboration in Internet systems, as well as age- and textprocessing-based methods used to compute the large amounts of inf- mation in the Internet more or less automatically were all emphasized in most papers and discussions during the conference. Thereweretwomini-workshopsintheworkshopbecausesometopicsmay- ?uence communities and the Internet, and the other way around. Armin Mikler from the University of North Texas at Denton organized the workshop on Computational Epidemiology, considering several aspects of this brand new research area which requires fast exchanges of information from large areas. Helena Unger organized a mini-workshop on the Optimization of Urban Tra?c Systems (OUTS), showing the strong connection between social communities and technical systems, and many requirements to use distributed systems and the Net to collect and process current information in the right manner."