By analogy to cartographic representations of spatial worlds, Knowledge Maps provide an 'aerial view' of a topic by highlighting key elements and connections. Moreover, just as spatial maps simplify the world and can fuel controversy, maps of conceptual worlds provide vehicles for summarising and negotiating meaning. In conjunction with the UK Open University's Open Educational Resources OpenLearn project, we are investigating the role of such maps for both learners and educators to share -and debate - interpretations of OERs. In this brief update, we describe how a mapping tool (Compendium) has been integrated with OpenLearn's elearning platform (Moodle) in order to support tasks such as concept analysis, problem-solving, literature review, learning path planning, argument analysis and OER design.