In university courses as well as in MOOCs, Community Question Answering (CQA) systems have been recently recognized as a promising alternative to standard discussion forums for mediating online discussions. Despite emerging research on educational CQA systems, a study investigating when and how to use these systems to support university education is still missing. We stress that such a study should effectively take into account students' perceptions of CQA systems rather than relying solely on an analysis of their effective usage based on data available in system logs. This paper therefore systematically analyzes perspective of 182 computer science students from three universities located in three different countries on concept of educational CQA systems. Students’ opinions were collected using a questionnaire that was designed to assess conceptual issues of using CQA systems in university education, their core features as well as particular implementation of our CQA system Askalot. The analysis of collected responses based on non-parametric statistical tests revealed that there are various significant differences in the perception of CQA systems between different types of students (e.g. passive and active) and in different deployment settings (e.g. when using CQA in a small number of 1–3 courses during one academic year or in 50 courses for 5 years). The obtained findings supported by content and usage analysis finally resulted into the summary of 12 main characteristics of CQA systems which describe their suitability for mediating online discussions in different deployment settings and for different types of students.