http://www.thedailyswarm.com/headlines/breaking-people-who-watch-oprah-will-do-whatever-she-does-including-buying-records/ This is a tiny article about the influence that Oprah has over people that she reaches.
Read the Tripwire article; 30 second read.
http://www.thetripwire.com/news/2009/11/17/new-savior-of-music-industry-oprah/ There's one person who can make people buy music, albeit its mostly the people who don't know how to download illegally.