The article is an introduction to the development of Andersen's concept of textual tools used in knowledge organization (KO) in light of the theory of genres and activity systems. In particular, the question is based on the concepts of genre connectivity and genre group, in addition to previously established concepts such as genre hierarchy, set, system, and repertoire. Five genre groups used in KO are described. The analysis of groups, systems, and selected genres used in KO is provided, based on the method proposed by Yates and Orlikowski. The aim is to show the genre system as a part of the activity system, and thus as a framework for KO.