Canadian indie rock outfit Arcade Fire recently announced on Twitter that their new album Reflektor would be dropping on Oct. 29. The casual tweet, which was actually in reply to a fan, contained this strange image, and offered no details about the follow-up to their Grammy-winning album The Suburbs. Now, a massive, building-side mural has appeared in downtown Manhattan with the Reflektor icon, and the words “Arcade Fire 9 pm 9/9.” As Spin has noted, the same icon has started to appear in cities around the world. The release of the mural was followed by a tweet from the band’s news Twitter feed, @ArcadeFiretube, that read “Believe me, I understand you all want answers. I’m not at liberty to reveal what will happen I’m afraid. It’s HUGE though. #Reflektor”. Though we’ll probably have to wait a few weeks to see what’s behind the viral marketing campaign, we do know that the band has a busy year ahead. In addition to releasing the new record, which is being produced by LCD Soundsystem’s James Murphy, Arcade Fire is also scoring the upcoming Spike Jonze film, Her …