Following Piaget’s model of equilibration we propose that people engage in knowledge building by contributing new information to wikis and by restructuring existing articles because of cognitive conflicts. Using Luhmann’s theory, this conflict can be described as irritation. We propose that when people work with a wiki they have to see if their own individual knowledge matches with the information the wiki provides. This matching process can lead to different results: If people feel that the wiki’s information is congruent to their individual knowledge then there is no need for equilibration and people do not accommodate or assimilate, either internally nor externally. In contrast, if people feel that the wiki’s information differs from their own knowledge, there is a need for equilibration, which people can satisfy by processes of internal or external assimilation or accommodation.