A change in chart methodology leads to viral sensation “Harlem Shake” by Baauer  catapulting to No. 1 on the Billboard Hot 100.

Starting this week, YouTube streaming data will be included in the media tallied for the Billboard Hot 100, joining radio play, other social steaming media, and digital sales (imagine how long “Gangnam Style” would have been at No. 1 if YouTube had been added only a few months ago!).

“Harlem Shake” is the 21st song in the 55-year history of the chart to debut at No. 1, according to Billboard.

“Shake” knocks Macklemore & Ryan Lewis’s “Thrift Shop,” which topped the chart for four weeks, down to No. 2.  Rihanna’s  “Stay, featuring Mikky Ekko,” charges to No. 3 from No. 57, propelled by the new methodology and her Grammy performance. “Stay” is Rihanna’s 24th top 10 hit. She surpasses both Whitney Houston and the Rolling Stones, who had 23 each.

Will.i.am and Britney Spears’ “Scream & Shout” falls 3-4, while Taylor Swift’s “I Knew Your Were Trouble” stays at No. 5.

The Lumineers’ “Ho Hey” slides 4-6 and Bruno Mars’ “Locked Out of Heaven”  falls to earth, slipping 2-7. But it’s not all bad news for Mars, as his new single, “When I Was Your Man” inches 9-8.

Justin Timberlake’s “Suit & Tie,” featuring Jay-Z moves 8-9 and Drake’s “Started From the Bottom” makes it way toward the top as it flies 63-10.