Introduction: Rating scales evaluating the quality of teaching are widely used by academic institutions and have become increasingly popular in the World Wide Web. This study examines teachers' and teacher-education students' knowledge and experience with public online ratings of teaching quality and their attitude towards them. Method: Based on focused interviews, a questionnaire was constructed. Data was collected from 225 teachers at seven schools and from 538 teacher-education students at four universities in Germany. Results: 42 % of all students questioned knew that they could evaluate their professors on MeinProf.de, but only a total of 1.5 % had posted one or more ratings on this website. Analysis of the data showed that teachers were more reserved towards public online ratings than teacher-education students (p less than 0.001), that senior teachers were more reserved about them than younger teachers (p less than 0.001), and that females were more reserved than males (p less than 0.01). Conclusion: The results indicate that a teacher's age is the most important factor influencing attitudes towards public online ratings, which can presumably be attributed to an age-related difficulty in getting high ratings. (Contains 1 figure.)