As we continue to evolve and organize more of our surroundings, our influence reaches up in local control of natural phenomena through technological achievement and slopes out in locality. The global brain is a brain of the universe, but it's influence is limited to the event horizon of light beaming out from earth. There is no organizational closure, just relative influence. First just talk to itself, then ask a lot of questions, and eventually it will try to gain mobility and capability. How fast depends on how curious it is.
Money is blood.
It circulates fluidly and powers activity. A majority of the gbrain's thought waves will be built of e-commerce activity. Also, it would find efficacy in increasing levels of technology and energy. These require money. It would thus move tandem to human nature.