SungKyunKwan Scandal Soundtrack (OST) has sold over 100,000 copies based largely on the inclusion of music from JYJ (Jaejoong, Yoochun, Junsu).  The song, Chajatta (Chajada) hasn't received any official promotion in Korea because of the current conflict the members are having with their former Korean management company. 

Still, the song has generated a groundswell of support from fans.  So much support that the song was nominated for the top spot on the Oct 1st broadcast of 'Music Bank'.