People forget how online spaces are still, ya know, spaces. They're no different than a brick-and-mortar building where flesh-and-bone humans interact using their voices and body language. The only peculiarity is here we're using the written word only. It can be easy to forget that we're still dealing with people who have egos, emotions, and the whole package that comes with the human experience. So, for instance, we shouldn't be so quick to ignore the difference between commenting with dissent on somebody else's space VS writing your own dissenting article within your own fence. But we do, because both things look the same at first glance. And yet, they couldn't be more different. I'm sure if we did an experiment and translated that to in person contexts, people would start going like, "whoa, slow down buddy. Why are you walking in here full of self-righteousness as if you own the place? That's so weird".
Anyway, rambling aside, I found this article very insightful. The pitfalls ring true, and are things I've both seen and fallen for. :)