Baauer commands the Billboard Hot 100 for a fourth week with “Harlem Shake,” although the viral sensation logs a second straight week of declines in YouTube streaming. The chart’s No. 2 song, and former four-week No. 1, Macklemore & Ryan Lewis’ “Thrift Shop,” featuring Wanz, meanwhile, ascends to the top of the Hot 100 Airplay chart while holding atop the Hot Digital Songs survey.

“Shake” entered the Hot 100 at No. 1 three weeks ago, concurrent with the addition of U.S. YouTube video streaming data to the chart. (To recap: YouTube streaming data now factors 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.)

Online momentum for “Shake,” the viral smash thanks to the song’s (and dance’s) runaway meme (in which a person dances to the song alone for 15 seconds before others join in for the clip’s second half), declines for a second consecutive week, although not as sharply as last week; and, its totals are still far ahead of its closest competitors. “Shake” holds at No. 1 on the BDS-based Streaming Songs chart with a 10% decrease to 48 million streams, down from 54 million last week and 98 million the week before. Sales also slide by 19% to 186,000, as “Shake” dips 3-4 on the Hot Digital Songs chart. Still, the song passes 1 million in downloads sold to date.

“Shake” also slips in on-demand audio streaming and radio airplay. It retreats 15-16 on the subscription services-based On-Demand Songs chart with 6320,000 streams (down 23%). Its total radio audience weakens by 2% to 7.8 million, a sum not strong enough for “Shake” to yet appear on the 75-position-deep all-format Hot 100 Airplay chart. As pointed out in Friday’s (March 8) “Weekly Chart Notes” column, “Shake” is the first Hot 100 No. 1 not to reach Hot 100 Airplay since Taylor Hicks’ “Do I Make You Proud” in 2006. (Hicks’ ballad reigned largely due to sales following his “American Idol” coronation that year.)

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 climbs 2-1 on Hot 100 Airplay (120 million, up 3%). The track is the first Hot 100 Airplay leader for a debut rap act since B.o.B’s “Nothin’ On You,” featuring Bruno Mars, in 2010. “Shop” also tops Hot Digital Songs for a ninth week and, with 306,000 in digital sales (down 10%), extends its record for the most weeks (also nine) of 300,000 or more downloads sold.

“Shop” leads On-Demand Songs for a 10th week, marking the first domination of double-digit weeks since the chart launched a year ago this week. It tops the list with 1.6 million on-demand streams (down 23%). “Shop” holds at No. 2 on Streaming Songs (9.2 million, down 52%) and leads Hot R&B/Hip-Hop Songs for a ninth week.

“Shake” decreases by 11% in overall Hot 100 chart points and “Shop” drops by 4%, granting the former a two-to-one points lead over the latter for a second straight week. The margin had been approximately three-and-half-to-one in each of the first two weeks that “Shake” led the list.

Mars’ “When I Was Your Man” holds at No. 3 and claims the Hot 100’s top Airplay Gainer award for a fifth consecutive week, representing the longest streak since Maroon 5’s “One More Night” claimed the honor for five consecutive frames in September/October (and the longest by a male since Eminem racked five such weeks in 2010 with “Love the Way You Lie,” featuring Rihanna). The piano-and-vocal ballad rises 9-7 on Hot 100 Airplay (95 million, up 16%) and 7-6 on Streaming Songs (3.7 million, up 5%) and keeps at No. 2 on Hot Digital Songs (240,000, up 4%).

Speaking of Rihanna, her “Stay,” featuring Mikky Ekko, pushes 5-4 on the Hot 100 after reaching a peak to date of No. 3 three weeks ago (following her performance of the song at the Grammy Awards on Feb. 10). The love song surges 23-16 on Hot 100 Airplay (55 million, up 18%) and 5-3 on Hot Digital Songs (236,000, up 12%). It additionally crashes the 1 million downloads-sold barrier, becoming her 27th title (including featured appearances) to reach the sales milestone.

Justin Timberlake’s No. 4-peaking “Suit & Tie,” featuring Jay-Z, returns to the Hot 100’s top five (8-5) for the first time since it roared 84-4 seven weeks ago (following its first full week of impact). It makes identical 7-5 advances on Hot 100 Airplay (98 million, up 9%) and Hot Digital Songs (151,000, up 7%), surely aided by his duties as host and musical guest on NBC’s “Saturday Night Live” (March 9). He’s currently amid a week-long residency on the network’s “Late Night With Jimmy Fallon” ahead of the release of his third solo album, The 20/20 Experience (March 19).

Rounding out the Hot 100’s top 10, Taylor Swift’s No. 2-peaking “I Knew You Were Trouble.” descends 4-6; Drake’s “Started From the Bottom” regresses to No. 7 from its No. 6 peak so far; will.i.am and Britney Spears’ No. 3 hit “Scream & Shout” drops 7-8; Lil Wayne’s “Love Me,” featuring Drake and Future, returns to the top 10 at a new highpoint (11-9); and, Mars’ former six-week No. 1 “Locked Out of Heaven” slips 9-10 in its 23rd week on the chart (and 20th frame in the top 10).

Check Billboard.biz tomorrow (March 14), when all rankings, including the Hot 100, Hot 100 Airplay, Hot Digital Songs and On-Demand Songs, will be refreshed, as they are each Thursday. [Billboard.biz]