Many software systems nowadays aim for usability or accessibility from the effectiveness and ergonomics point of view. However, there still is lack of such ones that correctly use the domain dictionary, correctly describe domain relations and properties and implement the target domain processes via their user interfaces. This property is called ‘domain usability’. In this paper we describe the state of the art work and experiments in automating evaluation of domain usability. We designed and implemented multiple methods for evaluating some of the properties of domain usability via ontologies. As an implementation of the evaluation method, we present the DEAL tool for analysis of Java user interfaces with the new ADUE module and describe experiments performed with this tool.