Mozilla Labs, in cojuction with Adaptive Path (a company responsible for the design on MySpace) have produced a series of videos called "Aurora".
These videos are intended to showcase how future web browsers may operate. The video is intended to prompt discussion about the future of browsers, and how they will manage and enable interaction between users and sites.
The video is a little jerky for me, but the video (and an explanation of the concept) is at
http://adaptivepath.com/aurora/index.php