I do see 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.