Terrible manners and borderline-abusive behavior are prominent and consistent features of anonymous Internet communities, as all can anecdotally attest. My research partner at UT and I have investigated this in the context of religious/spiritual cybercommunities and found some revealing mapping failures between meatspace and cyberspace, in this regard.
We also note that there are social dynamics at work that resist this bring-out-the-worse-in-our-natures feature as the community moves closer to meatspace, as in Facebook, where most if not all of one's cybercompanions are also meatspace companions. A continuum can be observed, and the degree to which we disinhibit and let our ugliness loose upon others maps fairly evenly along the lines of social consequence. Those who belong to this community who think nothing of attacking or insulting others personally would be more hesitant to do so, of course, in fora populated by their co-workers, family members, and loved ones. The conclusion we draw is simple, very two-dimensional: some people, type aside, embrace social responsibility, tolerance and graciousness as an abstract matter of course whether there is consequence or not; we refer to such a person as a "grown-up." Others start throwing spitballs and punching others as soon as the teacher's back is turned. We refer to these as "children."