Jordan Roseman, a.k.a. DJ Earworm, posted his first mash-up of Billboard's Top 25 songs on YouTube in 2007, in what was at the time a one-off experiment to see how many songs he could fit together in one track. Five years later, his annual "United State of Pop" mix is a year-end viral staple, with millions of viewers checking in to see the year in pop music reflected through his dense, hyperactive musical lens. Each mix becomes its own song, a barometer of the national mood, and a pop-culture time capsule as narrated by the likes of Katy Perry, Taylor Swift, and Bruno Mars.

This weekend Earworm premiered his 2012 mash-up, "Shine Brighter" (embed at bottom). I spoke to him on the phone from his studio in San Francisco in mid-November, when he was still hard at work bringing it all together.