Enterprise Social Networks (ESN) have been gaining increasing attention both in academia and practice. In previous works, different user types were identified in ESN. However, there is no clear definition of value-adding users, their characteristics and how this type of user can be identified. Based on a literature review, we show that value-adding users are defined in different ways in respect to different objectives, for example spreading knowledge, vivacity of the network or real-time feedback. Each of the value-adding users shows different characteristics that are allocated to the following dimensions: network structure, message, behavior, and social network affinity. Based on the objectives and characteristics, we conduct a single case study, analyze a dataset of a cooperating company, conduct several interviews, and thereby identify value-adding users with respect to objectives. So, we can show that our approach is applicable, useful and that it is a valuable means to take decisions.