I do read what some students say about me in RateMyProfessors. But I know it's not really relevant because over the years I have been able to compare with the actual evaluations done by the majority of the students. Here are a few examples that show how those rates are largely irrelevant:
One semester I taught this course with 17 students. One student posted in RMP basically saying that I did everything wrong. On the anonymous course evaluations, 16 students wrote good to very good remarks, and one student wrote "everything wrong".
Often, reviews in RMP appear two or three weeks into the semester. Complete with opinions on how I grade.
Many of the reviews are clearly written from a point of view of "the important thing is an easy pass". I definitely do not teach to cater to such students.
Finally, I have never heard any discussion, neither official or not, about RMP in my faculty. The teaching evaluations carried by the faculty, on the other hand, play a role in tenure and promotion, and I know of promotions to full professor being rejected due to poor evaluations.