Anthropologists have claimed that our minds are designed for small communities, where we know about 150 people. Now a billion people are on Facebook, each organized into a network where every individual is in contact with about 150 people they more or less know.  Information flows on this new topology happed onto the internet.  Yeah, it could have been done better, but this may be the most interesting thing that has happened in human history.

For the majority of practical people, it will be amazingly helpful, with wonders yet to unfold. If they keep control of things, the social network could make the world a better place, more democratic, more peaceful, more educated.

But there is that minority of people who are fundamentally political, millions of them all thinking about how they can exploit the social network to launch a wildly successful political mass movement.  Is there a fatal meme?  Will someone invent or modify a religion or reactionary political movement that will sweep across a billion people and cause a catastrophy?