So I made the ever-regrettable mistake of getting pulled into a particularly nasty forum "discussion" last night. I didn't participate--I just watched from the sidelines. I'm fascinated by these things much like people rubberneck past violent car wrecks--it's a shame, you know, but the least they could do is show some blood.
I rarely participate, except when it comes to esoteric things like the negative income tax or the causes of inflation, because they rarely ever actually become nasty.
There's always been a few good solid theories as to why internet discussions can degenerate so quickly, and it makes sense: when you can post anonymously you can pretty much say whatever you want; and when there are no repercussions, who cares? It's not like not talking to your forum friends for the rest of your life is going to cause a major upheaval in your well-being. There is absolutely no incentive to 1) not be a prick; 2) craft your arguments better; or 3) participate without knowing all of the details. So it's not really a surprise.
Of course, I think there is another cause at work, and it can be applied more than just to internet forums: we all see the world through our own lenses, and it's difficult to adjust to see others. This is particularly true with the Internet, as you're just as likely to run into a Taiwanese or German as you are some guy two states over.
This isn't a new theory, nor it is particularly revolutionary. But so very few individuals have the ability to recognize it (myself included) that when presented often surprises people and keeps them in check.
I was discussing something the other week online. I don't remember the details, but it was something like "I can't believe state X has a 9% sales tax! They just want to take your money and spend, spend, spend!" I then pointed out that while they do, in fact, have a 9% sales tax, they also have no state property tax. The other individual had never lived in a world without property tax, so the thought never crossed his mind, even though it was a perfectly reasonable situation.
It's not really surprising that the main focus of these discussions is religion and politics, but I've always been surprised at the amount of venom spewed over a third topic: computer and gaming platforms. So help you if you claim the X Box is better than the Playstation, or even suggest to a Mac user that the PC has its uses. It can get...bad.
Of course, let's not get too relativistic, here. There are certain indisputable facets of an argument that can be held true regardless of the situation, and I'm not suggesting that people throw out their long-held beliefs just because some dude in Prague never heard of zoning laws. But if you were having an argument face-to-face, you would most likely 1) not engage in a debate if you weren't more or less certain of how the argument was going to be framed, and 2) probably know about 90% of your participant's background and information, so you can make some fairly legitimate assumptions. On the internet, neither of these things apply. Adjusting the emphasis of your arguments--not necessarily the content--is valid when you aren't certain of the situation everyone else is in.
Here is another example: a few years ago I read about an American who went to Europe and asked several residents how many executions the United States participated in each year. The results pretty much indicated they assumed there were dozens per week. When told that it was more like two dozen a year, they absolutely refused to believe it. They've lived in a world that has no death penalty, and so don't know the process or frequency or reasoning, and have been told repeatedly that America does it all the time. Their assumption is that the Yanks chow through convicts like an assembly line, not realizing that--recent DNA evidence to the contrary--the process is quite judicial and time-consuming (and, if it weren't for Texas, pretty rare). But to most Europeans, they have been told otherwise and, mixed with erroneous assumptions, have formed a reasonably hard-core belief that is remarkably wrong.
I realize this pretty much sounds like a "just can't we all get along?" type of position, but I feel differently. It's a call to become more educated before you debate--not about your own convictions, but the reasons why your opponent may differ. Granted, the nature of the internet is not going to allow you to do that--you have no idea the background of the people participating, and there are usually dozens of differing backgrounds from around the world. But if you're looking to have a healthy debate instead of standing atop the mountain of slayed carcasses proclaiming that you were, in face, right all along, it's worth learning just as much about your opponents as your own convictions.