||Classically, poster sessions and similar individual contributions in exhibitions are evaluated with paper-based scoring sheets. This type of evaluation typically suffers from low response rates and depends on the memory of the attendants. In this work we propose a pervasive system that aims to fully automate the evaluation process. The key assumption of our approach is that the cumulative time people spend in front of a poster is a measure of how much they like it. The challenges associated to this hypothesis are twofold. Firstly, monitoring of persons within a given distance of the poster is needed. Secondly, the measurement of time spent is biased regarding the crowdedness of an area, since posters in frequently visited areas receive more attention than posters in quieter areas. In our approach, we use an ultrasonic range finder to measure distance profiles of people to posters. From these profiles, the time during which people are interested in a specific poster is calculated. Furthermore, the crowdedness in an area is found from the distance profile and serves to estimate the bias. Using these quantities, the appreciation of the attendants for each poster is determined.