To me trolling is making a negative comment without giving a reason and a suggestion for improvement, or making a negative comment outside of the artistic merits of the work. Flaming is one step up from trolling: saying something to intentionally offend or start an argument. We've had some flamers here once in a while too. Trolling: I hate this, it's stupid. It's too sweet and sappy to be able to stand. This is crap. This is offensive to all decent people. You're work makes me sick. I don't like this kind of crap. If you're going to say something negative, then make a suggestion for improvement. Saying something is crap is just rude. Say you don't like it, give the reasons, and make a suggesion for improvement. Negative content opionions don't help anyone. If something someone does doesn't agree with your belief structure, then go on and don't leave a comment, and avoid their work. My rule is that if I can't think of saying something to someone's face, I'm not going to type it in the comment. We're supposed to be helpful here. If you can't help, then go on. And whatever you say, try common curtesy.