What is a terrorist?

On a forum I frequent, there is a rather animated discussion concerning this article. I'll spare you the gory details of the thread, but, suffice it to say, after a brief digression of what constitutes thievery, it's morphed into a discussion on terrorism.

One poster maintains that, since a group like ELF or ALF hasn't actually killed anyone yet, their not really terrorists. My contention is that these groups, while not in the same calibre as Osama bin Laden, IRA or PLO, they are certainly in the same ballpark. Terrorism, in my opinion, is the use of force or the threat of the use of force to effect a change in the social order or political climate.

Protesting in the street and chanting "Bush lied, people died" is not terrorism. Sending an envelope laced with anthrax is. The same thing goes for starting fires or releasing lab animals into the wild. Both cause danger to the people in the area, and the fire certainly causes a danger to the personnel who have to respond. The fact that ELF hasn't killed anyone yet is more a factor of luck than a sincere desire for peaceful redress of grievencess on their side.