"Somebody That I Used To Know," the Sting-esque earworm of a single from Belgian-Australian singer-songwriter Gotye, has ascended to the peak position on the Billboard Hot 100 in its 15th week on the chart. Have a listen, if you've somehow managed to avoid its rise so far. It's a great song, but its popularity is particularly notable for two reasons.

  • 1. Having replaced fun.'s "We Are Young" at the summit, this marks the first back-to-back No. 1s on the Hot 100 that also hit No. 1 on Billboard's Alternative Songs (formerly Modern Rock Tracks) tally. Here's Chris Molanphy in 100 & Single, his reliably brilliant chart column for Sound of the City:

  • It's hard to overstate how exceptional it is that the big pop chart is commanded by a pair of alt-radio tracks at the same time. Last week, when Gotye was still at No. 2 on the Hot 100 behind fun., veteran chart reporter Paul Grein offered this startling statistic in his Yahoo! Music column: "This marks the first time that the top two songs on the Hot 100 were both #1 (or even top 10) hits on the Alternative chart."

  • So alternative is back. Dust off your flannel so you can wear it to the Buffalo Tom show you're sneaking out to attend tonight. (Well, maybe. Gotye's rise might also just be a weird blip, as Molanphy goes on to argue.)
  • 2. This marks the first No. 1 for a hit that was born viral. The original video (watch it above) has almost 170 million views on YouTube, while the cover version of five people playing it on one guitar has netted over 92 million views. Gotye's video dates back to July 2011, and the track has had kind of a slow burn worldwide (it's been No. 1 in almost 20 countries by now). It got another push after appearing on both Glee and Saturday Night Live, so the song has legitimate industry momentum. So far, it's done what Kreayshawn, Rebecca Black, Antoine Dodson, and Lana Del Rey have thus far not managed: it went from viral sensation to actual sensation.