The exciting Topic Maps (TMs) are an ideal catalyst for mutual learning experiences for proponents from the partially overlapping communities of Knowledge Organization (KO), Knowledge Management (KM) and Information Technology (IT). A long-term goal would be a tutorial white paper on the relationship between KO, KM and TMs, together with free reference software. KO is interested in optimizing the organization (the conceptual access structure) of knowledge repositories to support easier retrieval, creation and sharing of knowledge for user communities. TMs can indeed play an important role within KO: Together with related technologies, they have made it easier to provide innovative KO services. With TMs you can define arbitrarily complex knowledge structures and attribute them as metadata to information resources. Decentrally creating, maintaining and exchanging even more heterogeneous metadata is a powerful basic service of high interest for a broad range of applications. However, sooner or later you have to cope with the new semantic heterogeneity and come up with strategies to achieve better semantic interoperability. How could TM-based services alleviate the pressing KO problem of how to reorganize, enhance and semantically integrate heterogeneous subject data? Dedicated to this question, this talk takes a KO perspective: By sketching three typical scenarios in which heterogeneous metadata occur, it shows how classical KO challenges reappear with TMs, but also that TMs may be of value. Because the authors of the TM standard were right in not prescribing the application semantics of the structured link network, the widespread use of large-scale TMs will aggravate the well-known problem of the comparability and compatibility of KO schemata. A closer co-operation between the communities could aid the potential of TMs for KO/KM. Fortunately, the TM community has already started the fruitful exchange by discussing KO-relevant topics. Because of the flexible orientation of TMs towards usage contexts, especially user-oriented indexing should benefit from TMs. Approaches for achieving semantic interoperability within a layered model of decentral information provision are briefly presented as background against which further directions of KO with TMs can be discussed. One consequence for KO is that its methodology must be partially redesigned to take collaborative knowledge building activities on distributed resources more into consideration. This article also asks about the relationship between TMs and other means to computationally handle semantics in next-generation ontology- and agent-based knowledge services. In the end, possible further research towards this vision is suggested.