The popularity of the term Free Speech is something the Internet community inherits from its American roots. The FirstAmendment says:
The Universal Declaration of Human Rights covers similar ground in articles 18 and 19:
Article 29 places some limits on these (and other rights): they are subject to such "limitations as are determined by law solely for the purpose of securing due recognition and respect for the rights and freedoms of others and of meeting the just requirements of morality, public order and the general welfare in a democratic society", and "may in no case be exercised contrary to the purposes and principles of the United Nations".
Similarly, article 10 of the European Convention on Human Rights, states:
Thus, in many other countries of the world, however (OpenSociety or not), Free Speech has a less prominent place than in the USA. There is censorship to ban criticism of the government, ban pornography, ban fascist propaganda, etc. To people living in such a country, the term Free Speech might not carry the exact same connotation as to a citizen of the United States.
But even within the US, things are not as clear-cut. When the US intervened in Afghanistan in 2002, for example, a lot of people criticized the approach taken by the Bush administration. Following some protest marches and discussions, a right-wing organization published a list of "non-patriotic" public figures. When challenged, they said that the right to Free Speech does not include a protection from criticism. To some, this sort of list-making is very troubling -- it could be read as a call to hate crimes, or at least intimidation. Others would claim that they were public figures to begin with, and they made public statements, so they should expect public criticism. The questions is not easy to answer, and therefore what is and is not referred to by the term Free Speech remains open to discussion.
As set forth above, the ideal of FreeSpeech is peculiar to Americans and is grounded in the United States Constitution. However, even in the context of the First Amendment, the United States Supreme Court has created a number of qualifications and exceptions to the unequivocal statement that "Congress shall make no law. . ." First and foremost among these qualifications is the requirement that "state action" be involved in the abridgment of FreeSpeech before a person has standing to seek relief in a United Stated District Court. Beyond this initial burden of proof, the Court has distinguished "fully protected speech" from other forms of lesser-protected speech, such as "commercial speech," as well as stating that many forms of speech -- i.e., e.g., obscenity and child pornography -- are "unprotected speech." In other words, many restrictions on FreeSpeech are totally legal under the Supreme Court's interpretation of the First Amendment.
All this raises the question of why FreeSpeech is supposed to be a GoodThing. The reason that the founding fathers of the United States considered FreeSpeech to be so important was because it allowed the citizens of a democracy/republic to criticize the government and hold government actors accountable. However, in a much larger context, FreeSpeech is associated with the metaphorical "marketplace of ideas." As such, advocates of FreeSpeech tend to use arguments that parallel those of free market libertarians. -- DavidPrenatt
As noted above, speech can be a form of violence, and some of the worst abuses are designed to be effective but deniable. To paraphrase Oliver Wendell Holmes: "The right to flap my lips ends where the other man's ear begins". -- NathanielThurston