We share pictures and video, we screenshare, but everything we share has limitations that frequently hinder productivity. Take, for example, a piece of buggy code. Reproducing that bug could take unknown steps that require random, hopeful use. Wouldn't it be better if you could just take a snapshot of the application, and run it that way any time you wanted later, or share it with others? That's exactly what Carousel does. It's a more user friendly way to do checkpoint restore, so that you can save running applications and start them back up that way later as many times as you want.
It's also a collaboration tool. You're in a video call on Moxtra? Share your running application with others you've connected to in the call.