The printing press was one of the main factors making the reformation possible, which later on led to the thirty year's war. So it's actually a good example of how technology has unintended consequences.
Recent historians have been looking at how the printing press was more an instrument of state power than anything else. Remember that printing shops were state-controlled and heavily censored (_The Great Cat Massacre_ has a chapter on print shops in 18th-century Paris); most of their output was royal decrees, propaganda pamphlets, and books friendly to the regime in question.
The Reformation began for good reasons -- the Church had been dragging its feet on internal reforms for hundreds of years, and finally implemented these reforms in the Council of Trent, after the Reformation began -- but its spread was normally something that governments did to their people, not something that people chose for themselves. It wasn't an extension of liberty. Henry VIII and Edward VI flooded England with mercenaries, for example; in the Germanies, whether to turn Protestant or not was a decision made by rulers (who were legally entitled to compel their subjects to follow them; some converted to Lutheranism, seized Church property, and then switched back to Catholicism, and persecuted subjects who were slow to make the change each time). First-wave Protestants -- Lutherans and Anglicans -- generally had less religion rather than a different religion; even today, there are conservative branches of the Lutherans and Anglicans who are negotiating with the Catholic Church to return as whole congregations.
Calvinism was (if I remember rightly) never imposed from the top down, and typically took power through revolts by the middle class or the lower aristocracy; but Calvinist states tended to be oppressive, warlike, aggressively-middle-class theocracies -- very bad places to be poor or dissident. (_Albion's Seed_ is revealing on this; the modern Islamic Republic of Iran is a less theocratic, less anti-commercial, less oppressive place than 17th-century Puritan Massachusetts was.)
