[mgkimsal]

You're on to something, but even if the 'badness' on an individual basis is the same as 20 years ago, the volume has gone up more than linearly. As more people have joined and been able to find other like-minded folks, they've become emboldened to contribute more. And I don't think this has just happened in 'bad' communities - I've seen it happen in all sorts of communities - people connecting to other folks online has seemed to have this multiplier effect all over.

[vivekd]

I think a big part of it is anonymity encourages people to let out the worst aspects of their personality. I think if a forum required people to use their real identities you would see much less objectionable contact (but probably also a lot less interesting ideas)

[pjc50]

No, you'd see (as with youtube and G+) people putting out objectionable content under their own names. While genuinely vulnerable people would tend not to get involved for their own safety.

The problem is one of "lawlessness"; adhoc reprisals from your fellow netizens aren't an improvement.