A phenomenon common in places where a lot of people use mp3 players with headphones such as the iPod, Zune or whatever. The user plays the music so loud and is so engrossed in what they're hearing that their footsteps start to echo the bassline or lyrics of the song, to the point where they look pretty stupid.
iPod :ser: *vague ring of music as they walk past in a weird wat*
Non iPod User: Why's he walking like that? He looks stupid.
iPodless iPod User: He's iWalking.