SiriusXM tease

XM MARKS THE SPOT: We’ve got the latest adds on five key SiriusXM channels, including 20 on 20, which (along with the iTunes singles chart) serves as a reliable barometer for ever-shifting mainstream tastes. So what’s 20 on 20's top new track? Hint: It’s the same song that’s been #1 at iTunes all week. All is revealed right here. (11/27a)