We analyzed students' ratings and comments of their psychology instructors that were posted on RateMyProfessors.com and RateMyProfessors.ca to determine which features of a course and an instructor evoked the most positive and negative reactions. A content analysis of students' comments showed that instructors' characteristics(e.g., enthusiastic, organized) generated the most positive and negative comments; student development generated the fewest comments. Instructors' helpfulness and clarity were positively correlated with positive comments about their personality, teaching characteristics, and global quality. Although the psychometric qualities of the scales used on the RateMyProfessors Web sites and the representativeness of the students who made ratings on these sites are unknown, the focus of the students' comments was similar to those in studies of traditional teaching evaluations. (Contains 4 tables.)