Cyberbullies vs Trolls..?

So I do not know if it was just me but while reading Farhad Manjoo's article, "Web Trolls Winning as Incivility Increases", I felt that I might have been misunderstanding the definition of a troll previously. I always thought an internet troll was just someone who posted something - usually a comment - that would make others react in a defensive way. However, after reading about Zelda Williams's trolling incident, it's been made clear to me that that type of troll I had imagined is just one of many. I felt, though, that Ms. Williams's trolls were simply cyberbullies and I believe there's a huge difference between them. For me, I classify a troll as a person that just wants to get a quick reaction and just cause an online feud as to where I feel that cyberbullies intentionally try to make others online feel bad about themselves. Telling someone that they are at fault for a suicide is something I didn't see a troll doing. However we all have our different interpretations of things and I am not here to judge and just hope that my perspective isn't face-palm worthy.