I cannot believe that I am starting my 18th teaching year. I always start counting the years in September and this is 18. One of the things that I am mulling is what a popular instructor or popular prof means in academe. Does this reflect your enrollments? Is this term cast as a negative assuming that your course content is easy? I think the context mattters.
1. Hearing it from some colleagues it is clear that it cheapens your pedagogy and the depth of what you teach.
2. Hearing it from students varies, but it is mostly meant as a compliment.
3. Some colleagues clearly mean it as a compliment.
Overall, my sense is that the so-called popular instructors generally enjoy teaching. I think that is the difference.