"Thrift Shop": Cute underground rap song with a catchy horn riff, fun chorus and amusing music video. "Thrift Shop": Number one single. One of these statements about Macklemore and Ryan Lewis' breakthrough single true, and remarkably, the other might be true in a week or two as well. "Thrift" moves from #5 to #2 on the Hot 100 this week, deposing Taylor Swift's "I Knew You Were Trouble" as the chart's runner-up and knocking at the doorstep of Bruno Mars' "Locked Out of Heaven," in the top spot for a remarkable sixth consecutive week, easily Bruno's biggest chart hit to date.

It won't go uncontested, however. There's still Bruno in the top spot, Taylor lurking at #4 (with increases in radio play), and the Lumineers hanging around at #3 with the irrepressible "Ho Hey." And look out from an aerial assault from Justin Timberlake, whose new "Suit & Tie" debuts at #84 on airplay currency alone, with a week of iTunes sales likely to send it into the chart's top echelon—Billboard predicts a possible top five debut, though it'll need another week or two to contend for pole position.

Still, Bruno Mars, Taylor Swift, Justin Timberlake—all these no-names may end up being no match for the juggernaut that is Macklemore & Ryan Lewis. Looks like 2013 is gearing up to be a lot like 2012, with first-timers ruling the Billboard roost.