Here are some of my thoughts and impressions on freedom of speech after living in the USA as a British expat for a time (note that although there are many similarities, for the sake of comparison, I am focusing on British and American differences).
Anyway, generally speaking, I would say that freedom of speech in the USA is seen pretty much as an absolute and the vast majority of Americans are proud of it. They are also scared of losing it, however, and many, if not most, Americans across the political spectrum appear to believe that freedom of speech is under constant threat and has to be defended. Were freedom of speech to be compromised in any way, according to many Americans, it would be the beginning of the end of it.
In the UK, on the other hand, people are genuinely proud of freedom of speech, but is seen as a slightly more relative idea and generally dealt with in a more pragmatic way. British people also tend to just take their freedom of speech much more for granted than Americans do and there is no particular fear of losing free speech generally, certainly not in the way that Americans appear to fear its loss. The idea that it is a free country and you can say what you like is deeply ingrained in the British psyche, I would say, but there isn’t a great deal of passion in relation to it generally - in fact the British attitude seems virtually apathetic compared to the USA.
Metaphorically, I would say that Americans see freedom of speech as a very solid thing, rather like a canon ball (or maybe a brittle canon ball that can be broken if roughly treated?), and the Brits see it as something a bit more squashy, like a bean bag.
One of the main ways that freedom of speech is perceived in a subtly different way in Europe, compared to the US, is in regard to extremist politics. Pretty much all European countries have laws against stirring up religious, or racial hatred and people generally perceive this as a necessary evil, rather than an infringement on their rights. The reasons why these laws are there are fairly obvious, when you consider that historically so many European states were ruled by Nazi or fascist governments during the 1930s and 40s. This means that there is an underlying fear of rabble rousers stirring up hatred against minority groups and causing social disorder or worse, especially in countries like Germany and Austria. Britain has relatively mild laws on hate speech, but they are still there.
America was founded by people who had either experienced religious or political persecution, or wanted to do their own thing. So American ideas on free speech are more shaped by that experience. World War II also had a different impact on the USA to Europe.
It is also true to say that the American constitution was a positive assertion of freedom of speech as a value, whereas in Britain it was an historical development, with freedom of speech being achieved by default through restrictions being gradually removed. (Until the European Human Rights Bill was sealed into UK law recently).
Out of all the places that I could have chosen to live in the USA, by chance I happened to end up in Gainesville, Florida, where the notorious Koran burner, Terry Jones and his church, the Dove World Outreach Center are based (the group are actually atypical of Gainesville, which is a liberal college town). It was interesting to see how the Americans handled the situation. The first time round the media blew up a storm and top American officials ended up almost pleaded with them not to burn the Koran, with top army officers and even the president trying to persuade them of their folly and the potential damage they could do to US troops and US’s image abroad. In the end, Terry Jones called off his first book burning. The second time around, however, the media and officials more or less ignored the book burning and it went ahead with limited publicity.
In the UK, on the other hand, when there was a similar book burning by extremists and film of it put on Youtube, the people who did it were arrested and charged with inciting racial hatred. The differences in approach are pretty stark.
Overall, although I respect absolute free speech, I am probably still more at home with the pragmatic and relativist Brit approach at the end of the day. Some parts of US culture are difficult for me to understand. For instance, why the US allows publicity seeking hate groups like the Westboro Baptist Church to operate directly at funerals of young soldiers who have died. I accept that they should be allowed to express their view of the bible, no matter how distorted and disturbing they may appear, but why it is so essential that they have to do it so close to a funeral is difficult for me to grasp. I mean if they were forced to demonstrate two miles away, rather than under grieving relative’s noses, would it really signal the death of free speech? (Having said that, Britain has had its own problems with radical Muslims launching demonstrations at funeral homecoming parades held for British troops who have died in conflicts abroad.)
I guess the strength of the American approach to free speech is that because it is very nearly absolute, there is little room for it to be chipped away or reinterpreted in a way that reduces it. The weakness of it might be (at least from a Britisher’s viewpoint) that it can appear to pander to extremist elements and publicity seekers at times.