Since fallentimes just asked the same in an e-mail I can copy paste it here :-)

Basically it’s an advertising display. The way it works is that you have a motor with an attached circuitboard that has a row of RGB LED’s attached in a line from the center and out. When you spin the circuitboard and modulate the LED’s in the right fashion you can create the illusion of a display that’s hanging in midair. This is pretty computationally intensive for an embedded application (72 RGB LED’s that each need to update roughly 5000 times a second) so we used FPGA’s for it. The whole contraption has a built-in GSM phone module, and can communicate with a central server. The idea is that you take the display to a bar or some other outlet and plug it in. It will then automatically call in to the central server and request updates. Each display has a unique ID and thus it is possible to create content and advertising for individual displays, or groups of displays. If for instance you want to advertise in a certain part of town you can buy advertising time on only displays in the part of town you’re interested in. There’s a webbased tool for doing this.

Great idea, there was a clock display on Wired a few years ago that did something similar. Did you guys roll it out?

No unfortunately we didn't...

Our focus was on building a media channel, and we thought we would be distracted by doing consumer products as well.