Dan Zanger has been very successful, but considering the amount of individual traders in the world, it would be surprising if one or two had not made exceptional gains.
After all even in a lottery, where the average gain for all entries may be $1, most people lose a dollar and somebody makes millions, but is it worth analysing that persons number picking system.
I believe that in the long run most active traders lose money over time, I think roughly ten percent make money and probably 0.0001 per cent make the kind of money that Dan Zanger made/makes?
Just hope we're all in the ten percent.