The weekly iTunes albums and singles chart aren't always identical to the Billboard tallies, because downloading habits are sometimes way different from what people are picking up on the trip to the local Wal-Mart. And while much of this week's iTunes top 10 mirrors the action on the Billboard side, there are a few notable highlights that show where mainstream tastes diverge from Web ones.

Let's take the iTunes singles chart first. It is currently topped by mellow rockers Train with their comeback hit "Hey, Soul Sister," which is a few slots further down on the Billboard side. iTunes doesn't release specific sales figures, but suffice it to say it was another solid week for up-and-coming MC B.o.B, whose collabo with Bruno Mars, "Nothin' on You," is at #2 on the singles chart, followed by Rihanna ("Rude Boy"), Taio Cruz and Ludacris ("Break Your Heart"), Jason Derülo, ("In My Head"), Usher and Will.I.Am ("OMG") and Justin Bieber with Luda ("Baby").

And while he's M.I.A. on the traditional charts, mellow strummer Jack Johnson is at a solid #8 with "You and Your Heart," which bumps Miley Cyrus' "When I Look at You" out of the top 10. Rounding out the singles chart are Lady Gaga and Beyoncé ("Telephone") and the ubiquitous Black Eyed Peas ("Imma Be").

Over on the iTunes albums chart, Johnson is at the top of the heap with To the Sea, followed by the self-titled solo debut from former Guns N' Roses guitarist Slash, Usher's Raymond v. Raymond, Justin Bieber's My World 2.0 and Lady Antebellum's Need You Now, according to figures provided by Apple.

Holding strong at #6 is Lady Gaga's The Fame, which nosed out the second solo album from Jakob Dylan, Women and Country. Another jam fave, the John Butler Trio, slid into the #8 slot with April Uprising, which edged out the solo album from Sigur Rós singer/guitarist Jónsi, Go, as Erykah Badu's New Amerykah Part 2: Return of the Ankh slipped eight spots to #10.

Dropping off the top of the charts was the Wu Massacre album from Raekwon, Method Man and Ghostface Killah, comedian Robin Williams' Weapons of Self Destruction and the soundtrack to the Cyrus-starring film "The Last Song."