By Clark Collis
March 11, 2009 at 11:03 PM EDT

They pulled pretty much every conceivable marketing and publicity stunt to hawk their new CD, No Line on the Horizon. But U2’s 12th studio disc, which was released March 3, still sold only 484,000 copies in its first week. These days, not many acts would consider that number a disappointment. Still, U2 aren’t just any act: The Irish quartet’s last disc, 2004’s How to Dismantle an Atomic Bomb, shifted 840,000 units in week 1. What’s more, the ostensible heir to their biggest-band-in-the-world throne, Coldplay, moved 721,000 copies of last year’s Viva La Vida in the first seven days of its release.

So what caused U2’s middling sales? It wasn’t economics; fans could buy it digitally on for the ridiculously low price of $3.99. Nor was it due to a lack of promotional savvy. U2 opened this year’s Grammy ceremony and took up residence for five consecutive nights on Late Show With David Letterman. (The appearances did little to goose Letterman‘s ratings, perhaps indicating lukewarm interest in the album.) No, the villain seems to be lead single “Get On Your Boots,” which peaked — if that’s the word — at No. 37 on the Billboard Hot 100. “They didn’t have a clear radio hit,” says Jay Beau Jones, program director of Boston’s WBMX-FM. “When I first heard ‘Boots,’ I thought, It’s a good song. But when I first heard [Coldplay’s] ‘Viva La Vida,’ I thought, Wow!” Second single “Magnificent,” which sounds far more like classic ’80s-era U2 than “Boots” does, may provide renewed hope for Horizon, though. Says Amazon exec Craig Pape, “I was anxious for them to get that on the roster as a single. That stands out. I think the record will have long legs as people get exposed to more and more of the tracks.”