In a desktop browser? I can believe it. It's the Pinterest interface except horizontal. I see gradients, html5 video, opacity, position fixed. The only unbelievable thing about this video is the lack of loading time to load any content.
To me, Pinterest interface means random pictures and captions displayed in arbitrary sizes and order. When watching the preview video, the first thing I thought was "horizontal Pinterest".
That interface is entirely possible in a browser. Blurring the concept of software and web applications is entirely the trend that people should be pushing towards.
That said, it's a nice concept.