I think this model implies a certain marketing strategy. While achieving a critical mass might be impossible (read unlikely and hard to control) if you try for the world as a whole, it may be possible for a smaller one. Once you have a small group that is largely converted you can add other groups in such a way that you don't put out the fire by separating members of the first group.

It may be that a large part of the success of Facebook comes from the way they were able to use student bodies as small, self-contained networks, and then build from there.

It reminds me of building a fire with charcoals. If you keep them together you can keep them burning. If you can get a nice group going you can add to it bit by bit and build as big as you want. If you disperse them they die.

Our world has a million little self-contained networks. If you try to win some over perhaps some will succeed to the point that the network works for you. Then maybe you can add others.