OK Go's popularity is testament not only to the Chicago band's crunchy-guitar, power-pop flammability--in evidence since their late-1990s beginnings--but also to the mixture of media canniness and of-the-moment grace that allowed them to ride a wave of viral fervor surrounding their DIY videos posted on YouTube.com. Already well-regarded for their opening slots on They Might Be Giants' tours, and as the pit band for the traveling road show of NPR's THIS AMERICAN LIFE, the band got the extra publicity push they needed when their videos became some of the most downloaded in YouTube's then short history, and helped drive the sales of their second album, 2004's OH NO, through the roof.