Usually we have a nice cacophony of disagreements and competition going on in any particular industry. In rare instances, you find one voice on one side and the rest of an industry on the other. The lone voice is dismissed as a nutcase, a crazy person just seeking attention.
But listen carefully. They may turn out wrong but they have strong voices. And these strong voices wouldn't sound so strong if others were echoing them in chorus.
When they turn out right, a lot of people find themselves caught on the wrong side of the track and there is a lot of pain from the unwinding and purging. When they're wrong - no one notices. Think about the asymmetry of outcomes and ask yourself if it pays to be a gadfly.
I'll let you judge for yourself:
Georges Van Hoegaerden - Venture Capital Industry
Loren Feldman - Web 2.0
Michelle Rhee - Public Education
Maddox - Everything?
Czech President Vaclav Claus - Global Climate Change
Does anyone know of other gadflies to add to this list?