If free speech was a drug, would you get addicted to it? Or would you use it in small quantities, like caffeine? http://www.reallifecomics.com/archive/001005.html On the other hand, I drink a lot of caffeine when I need to, or when I want to. (Since I've started this journalism workshop, it's been a case of desire more than genuine need.)
Seriously, though, where is the limit to free speech? Does it stop at the end of the world, or the place where zombies go after they die again?
The abstract limit is either "when you violate another person's freedom of speech" or when "you shout 'Fire!' in a movie theater." In another words, when you are a hypocrite or when you lie and cause unnecessary chaos.
Here is the question about the "fire" thing: what if you have to shout "fire"? If someone had shouted "fire" and pulled the alarm at Virginia Tech, maybe less people would've died. If someone had evacuated Columbine under the pretense of a fire drill, then maybe the two shooters would've hit less people. On the other hand, the opposite could've occurred as well.