Well, I wish I know..
My area of research is music information retreival.
At the moment, I am working on behavioural music analysis. I am trying to use situational information, such as your current activity/mood/location to find the suitable music for this situation. Along the way, I study how different situtation change prefered music styles, and how this change from one listener to the other. If this is solved, you won’t be recommended your favorite metal song when you’re trying to sleep (well.. unless that’s what you like).