[rm999]

There's some discussion of companies that hold monopolies in free markets here: http://www.fool.com/investing/general/2012/04/18/for-monopol.... Basically, small companies with strong brands in slow-growing, niche industries. There's nothing really assuring their monopoly except that it's not worth trying to compete with them.

Regarding tech, the best example I can think of is TI and graphing calculators. They don't have a monopoly but they have a strong grasp on a niche industry - it's far from commoditized. I'm sure a company could create a clone, but I don't know if it would be worth the effort for such a small amount of revenue.