Korean fever is from the craziness for Korean boy band, girl group or dramas that follow by a good thing. Their craziness becomes a cause to learn Korean. I learn Korean for 4 years and most of student in class are teenager who crazy for boy band and girl group.
I used to ask them why they interested in Korean language they reply that they would like to know more about their artists. For example, when they watch Korean TV show , they will know what the artists said, especially they would like to know about the meaning of the Korea songs .