Online music sales continue to skyrocket at the expense of CDs. iTunes continues to be the leader of the pack, too, not only in online sales, but music sales overall. But a small rebellion is brewing against iTunes as artists become disgruntled with the hit they're taking on overall album sales thanks to the now-wildly-popular method of cherry-picking favorite tracks for download.

As we reported on Infinite Loop back in June, Kid Rock is one of the artists who have begun to speak out against what they consider to be an unfair distribution system in iTunes. Rock said at the time that iTunes was representative of the "old system," where distributors and record labels take money instead of giving it to artists. iTunes, for instance, pushes the a la carte music track system instead of allowing artists to sell music in album-only format. But selling millions of singles isn't necessarily as lucrative as selling far fewer full albums, and for some artists (we don't necessarily include Kid Rock in this category), there's the artistic vision realized only in the full-album experience.

Rock eventually decided that he was boycotting iTunes and not placing his new album on the popular online service. "In so many ways it's turned our business back into a singles business," Kid Rock's manager Ken Levitan told the Wall Street Journal today, referring to iTunes as "part of the death knell of the music business."

Since June, Rock has sold 1.7 million copies of his Rock 'n' Roll Jesus album, and sales have grown steadily in 19 of the last 22 weeks. Levitan says that, if the album was sold the iTunes way, most of those sales would have merely shown up as 99¢ downloads of the hit single from the album, All Summer Long. If the rest of the album was actually good enough to attract fans, then perhaps this wouldn't be so much of a concern; artists worry that many fans will never even sample enough other material from an album to find out if it's good or not.

Rock's success sans iTunes apparently prompted Atlantic Records, owned by Warner Music Group, to pull an album by R&B artist Estelle from iTunes, too (Estelle's album remains on Amazon's MP3 store, but is sold "album-only").

AC/DC has never put its music on iTunes either, the WSJ points out, and still managed to enjoy some success with 2.7 million CD sales last year.

And, of course, Jay-Z made headlines late last year for boycotting iTunes when his new album (at the time) American Gangster went on sale. "As movies are not sold scene by scene, this collection will not be sold as individual singles," he said at the time. The one thing we'll likely never know, though, is how much more successful these artists would be with the help of iTunes, if at all.

Music lovers: please change your buying habits

These artists' complaints aren't so much iTunes' fault as they are the "fault" of the evolving music market. There's an endless supply of other music stores that also sell music on a track-by-track basis, because customers just plain love being able to cherry-pick their favorite songs. Digital downloads just make that easier, but the practice itself has been around for decades.

Album sales have been plunging for some time now—they dropped a full 20 percent just last Christmas—and CD sales in general have been tanking for even longer. Some artists believe that actually cutting out iTunes and its per-track sales is the best way to increase revenue. It's a dangerous game, though; if consumers want only a single track that they could have for a buck but it's not available, will they purchase the whole album or simply grab the single from P2P networks?