You read and advance the text by rotating the scroll. Paperus is also expecting that you might want to listen to music, so there's a headphone jack at one end. There's no word on when it will be released or how much it might cost.
As I watch the video, I'm not sold on the idea. This effectively has a screen that is only a few lines tall and I read too fast for that. It's also no good for scanning large mounts of text. On the other hand, some people do read on small screen devices like BB. Perhaps there is a market niche for this.
Actually, I can think of at least one market for it. Add a pen to the far end and students will love it. They can load their notes on it and carry it into exams.