Nope, I don't believe that either. I'll follow the idea with interest, and I sort of want the theory to be true, but...once again...it's just too weird. If the universe is flat, how come it doesn't appear that way? Shouldn't theory conform to observation?
BTW: Roberto said that YouTube has just taken this video (above) down. Here's a more technical video on the same subject that might be of interest: http://theopenacademy.com/content/lecture-1-string-theory-and-m-theory
Apparently all these strange ideas spin off from the attempt to apply String Theory to cosmology. String Theory requires the existence of eleven dimensions and the existence of infinite numbers of universes. It's not regarded as proven but it's the operating assumption of a whole generation of cosmologists. But what if they're wrong?
The infinite universes concept is not without challenge. Skeptics like Michio Kaku claim that any equation that delivers an absurd answer like "an infinity of infinities" must be wrong. Count me with the skeptics. We don't even know the nature of dark matter and dark energy, which are held to account for most of what exists....maybe a theory of everything is premature.
I should mention another theory that's being bandied about lately...the theory that we're a simulation, a sort of video game on someone else's computer. This, I'm happy to say, isn't embraced by mainstream physicists, but it is being researched by a team in Germany. They figure that any simulation must occur on a grid of some sort, and that grid should be detectable. As a science fiction fan I love the idea, but....really.