Some good points, but I beg to differ with, "If social tools were creating real economic gains, we'd expect to see a substitution effect. They'd replace — disin

Some good points, but I beg to differ with, "If social tools were creating real economic gains, we'd expect to see a substitution effect. They'd replace — disintermediate — yesterday's gatekeepers." User reviews on sites like Amazon or Yelp (current legal issues aside, I have found it very useful) have largely disintermediated gatekeepers, to the benefit of customers.