This volume of Lecture Notes in Computer Science contains all accepted papers th of the 5 International Conference on Innovative Internet Community Systems 2 (I CS), which was held at the Sorbonne in Paris, from June 20 22, 2005. The previous four conferences in Ilmenau, Rostock, Leipzig (Germany) and Guadalajara (Mexico) developed the pro?le of this event. Traditionally, there are topics discussed in three main aspects. All of them must be considered in a united manner in order to investigate and understand the emergence and evolution of communities in the Internet: knowledge about...