Creation of a Global Brain

Correlations between mental behaviors and brain functions
  in brain injury cases
  in brain imaging studies
  via electrical stimulation of brain areas

Either these are mere coincidences,
  or humans will build intelligent machines
  and super-intelligent machines
  within about 100 years, I think

Humans, machines and the net will form a global brain
  what will be its nature?
  answer by analogy with human and animal brains