I love flash mobs, I hope to witness one someday. The cool thing about this one from a technical standpoint is the audio technology used. The participants were mic-ed with 30 Zaxcom recorders and transmitter/recorders. The interesting thing about Zaxcom units is that they can all be linked with an independent 2nd level radio network that communicates with them for control signals and synced timecode. So while this might normally be a very hard job for the Post editor to line up all the participants before starting the mixing process, here, thanks to the Zaxnet, he simply lines up all 30 by common timecode and off he goes. Slick.