I watched that a few days ago. Does indeed look very cool.
At first I was a bit confused about the 1-player vs. multiplayer aspects of it, but then I figured it out.
The game is 1-player, but you are connected to a server with thousands/millions of other players. When you reach an area where another player has a civilization, it copies theirs entirely, and downloads it to your computer, whereupon the computer ai takes over control.
So you don't have to worry about getting griefed by anonymous internet jerks, and you don't have the stale, repetitive opponents that a typical game provides because new content is constantly being uploaded by players themselves.
Basically the developers are admitting and embracing the fact that what 1 million gamers can create will be more diverse and exciting than what a 20-man developer team can.
Edited, Fri Mar 10 06:26:25 2006 by trickybeck