3Unify the Culture
Experts agree that the Internet has the magical power to turn normal people into fuckwads simply by granting them anonymity and an audience. But there's another cause that gets overlooked. Specifically, that a comment screen abhors a vacuum and will quickly fill it with assholes.
It works like this: Everybody is an asshole in some circumstances, and a nice guy in others. You go to Mardi Gras and scream for a lady to show you her boobs, but you don't do the same when sitting at the dinner table with Grandma on Sunday. As this article put it: "The largest determinant of behavior is the perceived social environment." But often on the Internet, there is no social environment.
To again use our own site as an example, the Cracked forums are consistently less angry and/or insulting than the article comments. Why? Because when you show up on the forums, you find yourself in an existing community, looking at a long list of threads and posts that establish the culture. Just a few minutes of reading gives you a sense of what is and is not acceptable.
But in the comments under an article (or YouTube video, or blog post), it's a clean slate. If just one dude comes in and submits "LOL WHAT A FAT BITCH" as the first post, he's set the tone for everybody and it will only go downhill from there. That's why modular post situations, where each conversation is completely isolated from the rest, make for some of the shittiest posting. A man sees an empty room and says, "Well, nobody here, guess I can flip out my dong."
So how do you fix that?
Universal Moderation Policy:
Something like this has been proposed by some prominent bloggers calling for a blogger Code of Conduct.
Some kind of guidelines for what is and is not acceptable in the comments would be drawn up, and everybody who agrees can adopt it. Those sites would be marked with some kind of symbol or badge, just as copyright and Creative Commons symbols indicate at a glance how intellectual property can be used.
In a world where those badges are common and commonly recognized, even looking at an empty comment box would let the poster know what's acceptable there.
Not the actual badge
Obviously a Lemonparty spammer won't see a badge and think, "Oh, you mean you don't want me to act like a douchebag? I do apologize, kind sir!"
But huge chunks of the population will modify their irritating behavior if you make it clear it's unacceptable (theater chains that reminded patrons to turn off their cell phones--and kicked out people who didn't--saw immediate results). For some people, they just need a sign in that empty room saying, "NON-COCK EXPOSURE ZONE" to keep their pants zipped. Give it to them.
And if that doesn't work...
2Up the Stakes for Membership
We've established that anonymous communication makes people assholes. But it also works the opposite way: Real life, in-person communication suppresses many of us who wish we could be assholes around the clock.
In the real world, getting a bad reputation can screw us over in countless ways, from losing future favors to getting punched in the nuts. A whole lot of people are civil for purely selfish motives. The Internet strips all that away.
Online you can drop by a blog and create an ID in seconds. You have absolutely nothing invested in it or its reputation. With that cardboard persona, you're free to rip shit up and if people get pissed, who cares?
Hell, you can even log out, create another ID, then join the others in their condemnation of the first ID. The rewards and consequences are all gone; your inner asshole is free to emerge.
This is why people tend to be less obnoxious in something like Second Life. Users there have an investment in their avatars, in time and energy and--usually--money. So how do you extend that to the rest of the web?
Charge Money for Membership:
When SomethingAwful.com started charging to join their forums a few years ago, it had the dual effect of raising cash for the site and slashing the number of retarded posters. It was just a one-time fee of $10--the cost of a few ringtones--but still far more than what some 13 year-old troll will pay to pop in and call Zach Parsons a fart zeppelin.
There's no realistic way to do this at the moment, but fast-forward ten years and don't be surprised if every major site makes you stick with the same user ID (maybe the one your ISP assigned you). And don't be surprised if that ID happens to look a whole lot like your real name.
I know, I know. You're saying, "But nobody wants that! That can only happen if they passed some kind of law or something ending anonymous Internet use!"
Well, that's why #1 is...