How do you find new music for your collection?

The topic should be moved to the music section.
I find almost everything on Last.fm.

4) I search on Last.fm/VKontakte, etc.

Why did you put them together? :(

There are two main folders. The first one (100GB+) contains everything I've listened to before (a lot of mythology-related music), and the second one contains only J-Pop and K-Pop.