Using facebook to emabrass or hurt someone. This can include creating fake accounts, changing someone's existing account or posting embarassing messages and photos.
"Someone created a fake account in Troy's name. He was the victim of Facebook Terrorism."
The act of tagging a photo in Facebook incorrectly with the intent to cause humiliation and/or yuks knowing full well that the photo will be sent through the target's News Feed for all friends to see.
Dude, Tori just pulled some Facebook Terrorism and tagged me in a photo of a bum sleeping on the street. That shit went out to my friends in the News Feed. Suxor.