It's strange to realize it but freedom of speech is unique to America. There aren't any other countries that give it the reverence that we do. A recent example is Canada's Human Rights Council which prosecuted journalist Mark Steyn for an except from his book America Alone. Canadian Muslims were offended by the book and, in Canada, it is a crime to offend anyone. More details here.
When asked about free speech, Dean Steacy, an investigator for Canada's national commission, said "Freedom of speech is an American concept, so I don't give it any value."
This is true for most of Europe where Hitler's writings and Holocaust denial are imprisonable offenses.
Europe's reaction to the Muslim cartoons was mixed and strained. Some countries apologized for allowing their media to print anything offensive.
Of course, the rest of the world is even less free. Egypt and China have arrested bloggers. Hugo Chavez shut down an opposition TV station.
It's hard to imagine any of this happening here but why are we different? Most of the world would say that we are out of step and need to change our laws. The UN suggested that there be international limits on offensive speech.
Regardless, free speech in America is not only afforded constitutional protection, it was the first freedom so protected. Our unique history has a lot to do with this.
During the colonial period from the mid-17th to the mid-18th centuries the English government didn't take much interest in colonial affairs. This changed after the French and Indian War when the crown wanted the colonies to pay for their own defense and tried imposing taxes. The colonies wanted to choose their own taxed and objected. This dispute was a major cause of the American Revolution.
At the same time there was a philosophical debate going on as to the proper relationship between a government and the governed. Practices that had been considered normal such as presumption of guilt were questioned.
After the Revolution, the first attempt at creating a national government with the Articles of Confederation failed. The Constitutional Convention was an attempt at creating a stronger government. Many of the delegates had been dissidents under British rule. They were wary of giving the new government too much power and they wanted to preserve their right to dissent. Accordingly they enshrined what they considered essential liberties in the Constitution where they would be difficult to change.
Jump forward a few decades to the French Revolution. The French talked a lot about liberty and equality but the post-revolutionary period in France was called the Terror for a reason. Rights were more by class than by individual. Marx and the other early socialists picked up on this class warfare and it infected European thought which in turn infected Canada.
So in Canada it is more important for a class of people to be protected from having their feelings hurt than protecting the individual right to free speech. The presumption of innocence is also thrown out. In the Canadian tribunals, an accusation means guilt.
Freedom of speech is not a given in the US. There are constant attempts to criminalize hate speech. Democrats are hoping to revive the Fairness Doctrine for radio which would be used to silence conservatives. Foreign laws are being cited as justification for US court cases. CAIR constantly claims Islamophobia.
If we are not careful we could see free speech vanish within out lifetime.