stylings of d.j. robby drums. >> we're going to hear soon from the piano guys. a lot of people know they actually became a youtube sensation after these four guys from utah just started playing the piano the brilliant way they do and put it online. one example of modern technology making people famous, probably quite appropriate for somebody who used modern technology twitter effectively to become president. >> we're not sure of this, but we think it's likely that this is the first youtube sensation to play at a presidential inaugural concert, although dana bash, as always, invokes the beaver claws and says it's possible that justin bieber played an inaugural. >> not sure. >> always the bieber clause, ms. bash. >> that's all i got.