Have not read it yet but there is a good review at Science Daily. In it Dr. Hayes is quoted claiming that pirates were backed by financeers, supported by the state as long as they paid taxes (privateering) and even had their own financial paradises in places like Tortuga and Madagascar. Pirates also ruled themselves in a democratic manner, what actually appears as a precedent of human rights... but to the exclussion of all others.
I'd argue that there are other precedents for corporations and democracy, though. The first ones can be traced already in Renaissance Italy, while the latter is found also in pre-Modern times in places like Switzerland and the Basque Country among other places. But still Hayes' idea is food for thought, specially as Capitalism and the now mainstream political theories of social contract appeared rather coincidentally not long after the golden of age of piracy. Piratic apogee was in the 17th century and the modern political and economical theories and praxis got consolidated in the 18th century.