This paper discusses the relative advantage offered by online Students' Evaluations of Teaching (SET) and describes a study conducted at a Canadian university to identify critical success factors of online evaluations from students' point of view. Factors identified as important by the students include anonymity, ease of use (of both SET survey and system), accessibility, publication of results, subsequent adjustments to the course, SET survey redesign, system reliability, incentives, reminders, and conveying the importance of the SET survey to students. We discuss key implications of the factors identified to faculty and survey administrators. (Contains 3 tables and 2 figures.)