It's not quite as anarchic as it sounds--views only count when the video's usage is "authorized," meaning YouTube kindly asks you to buy it--and it's not as sudden as it feels, according to an article in the New York Times. But it sounds very anarchic, and it feels extremely sudden, so you'll be forgiven for imagining that the charts shifted completely in the space between "Guy in mask not doing the Harlem Shake" and "everybody not doing the Harlem Shake."
But as surprised as I was by the timing, I'm not sure I can blame them for the move. They've already watched one of their charts become completely irrelevant.
The Hot 100--that's Billboard's singles list--still tracks popular music pretty well. Starting about a year ago you'd get the three ubiquitous summer songs--"We Are Young," "Somebody That I Used To Know," and "Call Me Maybe"--cameo appearances from Taylor Swift and the inexplicably multi-hit-wondrous Flo Rida, and longer stays from Maroon 5, Rihanna, and Bruno Mars. Most recently Macklemore and Ryan Lewis's "Thrift Shop" had a month-long run.
All that sounds about right. Whether you wanted to or not, you probably heard all of those songs several times over the course of the last year.
By comparison, Billboard's albums chart--once much more important to music-industry-watchers--is a complete mess. Topping the Billboard 200 over the same time period are such cultural phenomena as Lionel Richie (two weeks running), Adam Lambert, Linkin Park, the Zac Brown Band, dcTalk refugee TobyMac, and Matchbox Twenty and Dave Matthews Band (back to back.) Oh, and Adele's 21, which was the best selling album of 2011 and 2012.
At some point post-iTunes, albums stopped measuring broad cultural vitality and started measuring the ability to muster a narrow fanbase that likes physical media--that is, bands that tour well, down-on-their-luck or aging superstars, CCM acts, country artists, et cetera. Exactly the opposite of what it measured, say, in 2000, when 'N Sync, Eminem, and Santana collectively held the top spot for more than half of a year.
The Hot 100 was in no immediate danger of the same fate, but it had lost its edge. If you look down the list you'll see exactly the phenomenon it missed in 2012--the piece of musical history it wasn't able to relate to us.