The Billboard Hot 100 undergoes a major shakeup this week, as YouTube streaming data joins the chart’s methodology. Fittingly, “Harlem Shake,” the viral smash from Brooklyn producer Baauer, roars onto the ranking at No. 1.

As announced, Billboard and Nielsen have revealed that U.S. YouTube video streaming data has been added to multiple platforms, which includes an update to the formula for the five-decade-old Hot 100. YouTube streaming data is now factored into the chart, enhancing a recipe that includes digital download track sales (and physical singles sales), as tracked by Nielsen SoundScan, as well as terrestrial radio airplay, on-demand audio streaming, and online radio streaming, as tracked by Nielsen BDS.

“Shake” becomes just the 21st song (of 1,023 No. 1s dating to the chart’s 1958 launch) to debut at No. 1 on the Hot 100. Even more notably, it’s the first song to start at the summit by an artist essentially unknown prior to charting. Of the prior 20 No. 1 debuts, three were by artists making their first Hot 100 appearances, but all — Clay Aiken, Fantasia and Carrie Underwood — had built familiarity via months of weekly TV exposure on Fox’s “American Idol” (2002-05). Lauryn Hill also sent her solo debut “Doo Wop (That Thing)” to a No. 1 beginning in 1998, but she was, by then, known for fronting R&B act the Fugees.

Baauer (born Harry Rodrigues) has taken advantage of the digital era (and the Hot 100’s formula revision) to quickly make his hit the most popular song in the country. The track has surged thanks to the suddenly wildly popular “Harlem Shake” meme. (Its concept: a 30-second video begins with a person dancing to the song alone for 15 seconds, while other people appear unaware of the movement. Then, all participants join in for the clip’s second half.) Fueled by the song’s audio as a backing track, “Shake” debuts on the BDS-based Streaming Songs chart with an astounding 103 million weekly streams. The title does not appear on On-Demand Songs as only 309,000 of its streams stem from the online subscription services that contribute to that chart.

While “Shake” was released commercially last June, it didn’t begin to sell significantly until last week, thanks to the track’s viral momentum, when it moved 18,000 (up from less than 1,000 the week before), according to SoundScan. This week, it blasts onto the Hot Digital Songs chart at No. 3 with 262,000 downloads sold (up 1,359%).

The one element largely missing so far from the success of “Shake” is radio airplay. (Released on the independent Mad Decent label, it does not boast major label promotional backing). In the Hot 100’s Feb. 13-19 BDS tracking week, the song registered just 2 million audience impressions, garnering plays on 112 of the 1,235 stations monitored for the Hot 100. Latin pop-formatted WVOZ San Juan, P.R., leads all reporters with 25 plays for “Shake” last week, followed by dance KNHC Seattle. Still, the airplay is up sharply from the previous week, when the song logged a mere two spins nationally.

As “Shake” takes over atop the Hot 100 (and Dance/Electronic Songs, where it leaps from No. 12), it dethrones Macklemore & Ryan Lewis’ “Thrift Shop,” featuring Wanz, after a four-week reign. Showing just how strong “Shake” is in streaming, “Shop” registered an impressive 10.1 million streams in the chart’s tracking week (dipping 1-2 on Streaming Songs), but the figure is clearly exponentially lower than the 103 million for “Shake.” “Shake,” in fact, leads the Hot 100 with three-and-a-half times the overall chart points total of “Shop.”

Still, “Shop” leads Hot Digital Songs for a sixth week, scoring its highest weekly sum (412,000, up 6%) so far. With the track having banked six weeks of sales of 300,000 or more, it joins only fun.’s “We Are Young,” featuring Janelle Monae (seven weeks, 2012), and Gotye’s “Somebody That I Used to Know,” featuring Kimbra (six, 2012), as the only songs to rack as many such sales weeks.

On Hot 100 Airplay, “Shop” bullets again at No. 4 with 111 million impressions, up 8%. It leads Hot R&B/Hip-Hop Songs for a sixth week.

Beyond the flurry of activity atop the Hot 100, Rihanna adds her own headlines at No. 3, as “Stay,” featuring Mikky Ekko, vaults with top Digital Gainer honors from No. 57 in its second week on the chart. After she performed the ballad at the Grammy Awards (Feb. 10) and subsequently released its video, it bounds 25-2 on Hot Digital Songs (306,000, up 358%) and debuts on Streaming Songs at No. 7 (3.9 million). On Radio Songs, it lifts 74-57 (24 million, up 53%).

“Stay” becomes Rihanna’s 24th Hot 100 top 10, pushing her past Whitney Houston and the Rolling Stones (23 each) for a solo claim of ninth-place among acts with the most top 10s all-time. Madonna leads all artists with 38 top 10s, followed by the Beatles (34), Michael Jackson, Stevie Wonder (28 each), Mariah Carey, Janet Jackson, Elton John (27 each) and Elvis Presley (25). (Presley’s career, however, predated the Hot 100’s inception).

Will.i.am and Britney Spears’ “Scream & Shout” slips 3-4 on the Hot 100. It climbs 6-5 on Hot 100 Airplay (98 million, up 3%) and 7-4 on Streaming Songs (4.8 million) but plummets 2-10 on Digital Songs (158,000, down 3%). It passes 2 million downloads sold to date.

Taylor Swift’s No. 2-peaking “I Knew You Were Trouble” stays at No. 5 but benefits from the addition of streaming data to the Hot 100. The song has been withheld from most subscription streaming services but racked 2.8 million plays on YouTube last week, enabling a No. 10 start for the track on Streaming Songs this week. It leads Radio Songs for a second week (135 million, up 1%) and falls 5-11 on Hot Digital Songs (149,000, down 5%).

The Lumineers’ “Ho Hey” descends 4-6 on the Hot 100 (while topping Hot Rock Songs for a 14th week) and Bruno Mars’ former six-week No. 1 “Locked Out of Heaven” tumbles 2-7. Mars’ follow-up “When I Was Your Man,” meanwhile, rises 9-8 with the chart’s top Airplay Gainer award. The piano ballad powers 30-16 on Hot 100 Airplay (56 million, up 37%), holds at No. 4 on Hot Digital Songs with a 36% gain to 217,000 and pushes 18-12 on Streaming Songs (2.6 million).

Grammy Awards performer (and segment presenter) Justin Timberlake regresses 8-9 on the Hot 100 with “Suit & Tie,” featuring Jay-Z, although the track edges 8-5 on Hot Digital Songs (201,000, up 67%) and 10-9 on Hot 100 Airplay (71 million, up 9%), while holding at No. 19 on Streaming Songs (2 million). Timberlake concurrently debuts at No. 24 on the Hot 100 with “Mirrors,” which bows in the Hot Digital Songs top 10 at No. 9 with 163,000 after it hit iTunes early on Monday, Feb. 11. The song, due to be the second radio single from Timberlake’s March 19 album 20/20 Experience, was available either as a stand-alone track purchase, or as an instant-gratification download when a customer pre-ordered the album. (The customer was immediately charged for the track in either instance.)

Drake rounds out the Hot 100’s top 10 with top Streaming Gainer award-winner “Started From the Bottom” (63-10), which flies 32-8 on Hot Digital Songs with 168,000 downloads sold (up 185%) following its first full week of sales. The cut, the rapper’s 11th Hot 100 top 10, debuted last week after four days of sales impact, as it was released on Feb. 7. “Started” starts at No. 3 on Streaming Songs with 5.5 million streams, following its Feb. 13 video premiere. [Billboard.biz]