What you are looking at:
Over 3,000 apps-and growing-are dowloading every minute from the app store. This is live feed showing the activity of 20,000 popular apps currently on the store. Every time a customer downloads an app, its icon lights up (5min delay).

How Apple made it:
This hyperwall was built using the latest in Apple technology. It's powered by 20 Mac Pro towers running Mac OS X Snow Leopard. It was programmed in Quartz Composer using new OpenCL APIs. And it's shown on 20 synchronized 30-inch Apple cinema HD display. (less info)