iTunes

DOWNLOAD THIS: Columbia's Pharrell has, with the infectious single "Happy," done what nobody's been able to do for a while: He's dislodged Katy Perry's monster "Dark Horse" from the top of the iTunes singles chart. Meanwhile, Warner Bros.' Jason Derulo has dirty-talked his way to #3, and John Legend continues to make consumers swoon with "All of Me." While Frozen still dominates the album side (note Idina Menzel's "Let It Go" at #12 on the singles side as well), we note the power of Motown's Toni Braxton-Babyface collaboration, which continues to earn relentless TV exposure this week. Keep an eye on EMI Nashville's hard-edged Country star Eric Church, who's streeting Tuesday. Just outside the chart is Lake Street Dive, a neo-folk ensemble who turned heads on the Inside Llewyn Davis TV special and, more recently, on Colbert; their album, on tiny Signature Sounds, is at #12, and they've been selling out major-market venues. (2/7p)