Freedom of Speech has been hard fought for over the years, it is not a right that people in power really like. Freedom of Speech gives those in power or authority problems. People may use their power of speech to advocate for the overthrow of governments, make fun of religion, poke fun at our hero's or advocate a position with which the powerful disagree.
Democracy depends on the principle of free speech, but today there are those that would put limits (unreasonable) on Free Speech because of the Terrorist threat and because it fits their own agenda for power. In our society there are limits on free speech, you can't yell fire in a crowded room, or you can't (in Canada) advocate hate crimes, and most of us believe that these are reasonable limits. However, in the name of democracy our government is taking steps to limit freedom through new terrorism laws, and our mainstream media is controlled by powerful vested interests who have no interest in having people read/see the truth except as they see the truth.
In our society the ones who maintain the principle of freedom of speech are the writers, the cartoonists and bloggers on the internet and in mass media, who do not bow to the powerful or the religious fanatics who attack in an attempt to make us afraid. Fear is a two headed and dangerous enemy, fear can protect us and help us survive, but it can also make us take actions that are not in our best interests. The measure of our society and the future of our democracy will be determined by how we react to the fear and anger that we feel every time there is a terrorist attack. We cannot let those who want power to use our fears to gain control because when they do, we lose our freedom. In the face of danger and fear, we must keep our courage.