Baauer tops the Billboard Hot 100 for a third week with “Harlem Shake,” although the Brooklyn producer’s viral smash experiences a hefty decline in YouTube streaming figures. The chart’s No. 2 song, Macklemore & Ryan Lewis’ “Thrift Shop,” featuring Wanz, meanwhile, makes digital sales history with its latest weekly download total.

“Shake” entered the Hot 100 at No. 1 two weeks ago, concurrent with the addition of U.S. YouTube video streaming data to the chart. YouTube streaming data is now factored into the Hot 100 (and other genre charts), enhancing a mix of data 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” has risen to pop culture prominence thanks to the song’s (and dance’s) hugely popular meme (in which a person dances to the song alone for 15 seconds before others join in for the clip’s second half). Even Fox’s “The Simpsons” ribbed the craze in its opening couch gag on Sunday’s (March 3) episode (redubbing it the “Homer Shake”). Online momentum appears to have crested, however, as “Shake” holds at No. 1 on the BDS-based Streaming Songs chart, but with a 45% decrease to 54 million streams (down from 98 million last week). Sales also slide by 23% to 228,000, as “Shake” drops 2-3 on the Hot Digital Songs chart.

Still, “Shake” is gaining in on-demand streaming and radio airplay. It rises 17-15 on the subscription services-based On-Demand Songs with 820,000 streams (up 2%) and enters the Mainstream Top 40 and Rhythmic radio airplay charts at Nos. 38 and 40. Its total audience swells by 33%, but, at 7.9 million, it does not yet appear on the 75-position-deep all-format Hot 100 Airplay chart.

As “Shake” again rules the Hot 100 (and the Dance/Electronic Songs chart), Macklemore & Lewis’ “Shop” remains at No. 2 following a four-week reign and sets a noteworthy sales mark. “Shop” tops Hot Digital Songs for an eighth week and, with 326,000 in digital sales (down 10%), becomes the first song to log eight weeks of 300,000 or more downloads sold since SoundScan began tracking digital sales in 2003. It bests fun.’s “We Are Young” (featuring Janelle Monae), which racked seven such sales frames last year. With its latest frame, “Shop” passes 4 million in digital sales to date (4.2 million).

“Shop” sets another record: it leads On-Demand Songs for a ninth week, topping the eight-week No. 1 run of Gotye’s “Somebody That I Used to Know,” featuring Kimbra, for the longest command since the chart launched a year ago this month. It crowns the list with 2 million on-demand streams (down 3%). “Shop” holds at No. 2 on Streaming Songs (9.7 million, up 2%) and spends a second week at No. 2 on Hot 100 Airplay (117 million, up 2%). It leads Hot R&B/Hip-Hop Songs for an eighth week.

After “Shake” outpaced “Shop” with slightly more than three-and-a-half times the Hot 100 points total of the latter the past two weeks, “Shake” drops by 43% in overall points and “Shop” falls by just 4% this week. “Shop,” thus,” boasts a thinner, although still wide, lead of more than twice as many points as “Shop” this week.

Bruno Mars “When I Was Your Man” holds at No. 3 and claims the Hot 100’s top Airplay Gainer award for a third consecutive week. The piano ballad, fromUnorthodox Jukebox, the Billboard 200’s new No. 1 album (and Mars’ first), jumps 11-9 on Hot 100 Airplay (82 million, up 18%), marking his 10th consecutive career-opening top 10 on the tally. Only Mariah Carey (12) and T-Pain (11) have begun with longer top 10 streaks dating to the list’s 1990 launch. “Man” lifts 3-2 on Hot Digital Songs (231,000, up 1%) and 11-8 on Streaming Songs (3.5 million, up 12%).

Taylor Swift’s No. 2-peaking “I Knew You Were Trouble.” keeps at No. 4 on the Hot 100. It rules Hot 100 Airplay for a fourth week (126 million, down 4%).

Rihanna’s “Stay,” featuring Mikky Ekko, rebounds 7-5 on the Hot 100 after reaching a peak to date of No. 3 two weeks ago following her performance of the song at the Grammy Awards (Feb. 10). The ballad charges 36-23 on Hot 100 Airplay (46 million, up 37%), offsetting minor slips in sales (4-5 on Hot Digital Songs; 211,000, down 1%) and streaming (9-10 on Streaming Songs; 3.3 million, down less than 1%).

Rounding out the Hot 100’s top 10, Drake’s “Started From the Bottom” holds at No. 6; will.i.am and Britney Spears’ No. 3-peaking “Scream & Shout” descends 5-7; Justin Timberlake’s No. 4 hit “Suit & Tie,” featuring Jay-Z, is static at No. 8 (and passes 1 million in sales to date); Mars’ former six-week No. 1 “Locked Out of Heaven” stays at No. 9; and Swedish House Mafia’s “Don’t You Worry Child,” featuring John Martin, returns to the top 10 (12-10) after rising to No. 6 last month. [Billboard.biz]