I would risk to venture that the answer to these questions is "yes." Taking for granted that there are laws which bind us, such as it being a crime to lure young children to places where some predator may hurt them by lying about one's identity on the web, or the use of child pornography, there are areas which I am afraid some of us step over with complete abandonment of the ideals and values we hold in face to face conversation.
A few people I have known, sometimes for years, have treated me with derision, sarcasm, and contempt when formulating an argument to something I have said. I find this surprising, and sad, and amazed that they think my feelings are somehow different if I read it on a post, message, or via some electronic media than face to face. I think for the most part I have been well treated, but on occassion I am amazed someone would risk our friendship by thinking they could write something insulting, publicly, about what I have said and not think I would remember it when I see them again. This may be because I grew up in Newark, and disrespect is well remembered.
It is the pretense of anonymity in electronic debate that makes us think we can be nasty, especially if it is funny and dismissive. We not only feel as if we are equal with those with whom we disagree, but if we can ridicule them we feel we are superior. I suppose some ideas and positions deserve ridicule, but it is dangerous in person to so ridicule someone's position, or to assume that their hurt, shame, and anger after you have demolished them will be forgotten. In person we are somewhat more circumspect simply due to the fact that we don't want to get into a fight, but care for others should not simply be because they will pick up something and hit us with it.
Some of us love debate, we enjoy good reparte (sp), we are amused at clever sarcasm. I know I love to hear a sound and reasoned argument, and I especially love it if the argument follows the rules of logic, and even better if the conclusions are not just valid but true. Some of the worst examples however of ad hominem arguments are in those long trails of comments after some public posting where people have stopped making comments germane to the original issue and mock, demean, and curse at those with whom they disagree.
Just because one is clever in covering up insult, racism, vilification, etc. by using ostensiblly neutral phrases, name calling is still name calling. Insulting labels, equating views with what a general public would almost always despise, and simply not being fair or not giving someone the benefit of the doubt are far too frequent in electronic discourse. Exaggerating someone's point so that it no longer is actually their point, setting up a straw man with which they themselves would not agree, and then beating up on this new and irrelevant issue in an attempt to make our opponent seem extreme, stupid, and evil is just flat dishonest and wrong. If the reader is half way intelligent he will despise your crafty dishonesty, which they should. One would assume that no one wants to be a jerk in print (nor on the screen) and have everyone in the universe be able to pull it up to your mortification.
Of course this has become the pattern of both political talk radio and pseudo political television satire. It has become ruinous for kindness in disagreement. Recently a gentleman who works with very brilliant university students told me that students no longer like to have "bull sessions." My comment to him was that my observations have led me to believe that as soon as we realize we disagree with someone we don't want to engage with them, we want to destroy them. We all seem to want to be on stage, and on the web our disagreement is about playing to the audience, as if we win points or can count coup by our petty little stabs at someone's position. It is far too easy to be a bully in this medium.
Let me state that I bring this up not because I am afraid. I smugly feel (Lord, forgive me) as if most of the time I can fight for myself in any kind of writing or speaking, and it is not usually a fair fight. I can be as viciously cruel with my words and thoughts as anyone, I have made my living with words. This does nothing so much as give me more responsibility to treat people, even the really mean and pathetically dumb, with respect. Let me add some Scripture. From Psalm 34:12, "Whoever of you loves life and desires to see many good days, keep your tongue from evil, and your lips from speaking lies."(NIV) And again from Proverbs 18:21, "The tongue has the power of life and death, and those who love it will eat its fruit."
So, if you are mad at someone go see them and have coffee, or get off line and call them on the phone, or at least send a message instead of posting so only they can see it. Don't kid yourself, the amount of people listed on FB as friends are not really your friends, you need all the real ones you can keep.