[Double Naught Spy]

I would consider any of the mall-shootings, school shootings, etc, a "terrorist act"...maybe not in regard to motivation, etc, but with respect to the way they're carried out (multiple victims, public setting, etc).

Actually, it is motivation that is the distinguishing difference between a terrorist attack and mass murder or serial killing. Unless the attack is carried out against civilian targets for the purpose of bringing about social, political, or religious change, they are not terrorist attacks.

The United States has defined terrorism under the Federal Criminal Code. Chapter 113B of Part I of Title 18 of the United States Code defines terrorism and lists the crimes associated with terrorism.[24] In Section 2331 of Chapter 113b, terrorism is defined as:

…activities that involve violent… or life-threatening acts… that are a violation of the criminal laws of the United States or of any State and… appear to be intended (i) to intimidate or coerce a civilian population; (ii) to influence the policy of a government by intimidation or coercion; or (iii) to affect the conduct of a government by mass destruction, assassination, or kidnapping; and… (C) occur primarily within the territorial jurisdiction of the United States… [or]… (C) occur primarily outside the territorial jurisdiction of the United States…"

UN Security Council Resolution 1566, March 17, 2005 -a UN panel described terrorism as

any act intended to cause death or serious bodily harm to civilians or non-combatants with the purpose of intimidating a population or compelling a government or an international organization to do or abstain from doing any act.

So Columbine wasn't an act of terrorism. The DC Snipers were not terrorists. Many if not most church shootings are not terrorist-based, nor are mall shootings (at least not to date).