A snapshot look at the most notable jumps and drops on this week’s Billboard Hot 100.

-- B.o.B: B.o.B leads the Billboard Hot 100 for a second week and sends a second song into the chart's top 10. The rapper's first single, "Nothin' on You," featuring Bruno Mars, tops the Hot 100, while his "Airplanes," featuring Paramore vocalist Hayley Williams, goes to No. 9. Digital sales (160,000, up 16%, according to Nielsen SoundScan) accounted for 92% of the second song's chart points. A third track by the B.o.B, "Bet I," featuring T.I. and Playboy Tre, opens on the Hot 100 at No. 72. As previously reported, B.o.B's just-released debut album, "The Adventures of Bobby Ray," will vie for the No. 1 spot on next week's Billboard 200.

-- Usher: Up 8-6, Usher's "OMG," featuring will.i.am, scores the Hot 100's top airplay increase for a second consecutive week (53.3 million in audience, up 38%) and adds Digital Gainer honors (160,000 downloads sold, up 22%).

-- ”Glee” and Madonna: As "Glee: the Music, the Power of Madonna" debuted atop the Billboard 200, four tracks from the covers collection enter the Hot 100. Led by "Like a Prayer," which enters the Hot 100 at No. 27 and Digital Songs at No. 10 (89,000 downloads sold), the album's seven songs available a la carte sold a combined 220,000 downloads. The series' April 20 Madonna-centric episode additionally spurred interest in the Queen of Pop's catalog, with Madonna's original versions of the individually-available songs covered by the "Glee" cast moving 52,000 downloads, a 246% increase.

-- Miranda Lambert: Winner of three ACM Awards April 18, including top female vocalist of the year, Miranda Lambert notches her highest Hot 100 rank, as "The House That Built Me" vaults 55-30. Lambert's previous single, "White Liar," reached No. 38 on the Hot 100 in November. Her current hit jumps 13-9 on Hot Country Songs as the survey's Greatest Gainer (21.6 million impressions, up 16%).

-- Christina Aguilera: Christina Aguilera's "Not Myself Tonight" drops 23-49 in its second week on the Hot 100, after it charged onto the chart last week following its digital release. Though the track dips by 66% in download sales to 27,000, it breaks 59-49 on Hot 100 Airplay (22 million, up 13%) and 23-19 on Mainstream Top 40.

-- Alicia Keys: Last week's "American Idol" mentor/performer Alicia Keys soars 83-58 on the Hot 100 with "Un-Thinkable," with 14,000 downloads sold (up 46%) and 30 million audience impressions (up 37%). The track bounds 50-35 on Hot 100 Airplay.