Limit the reward for voting badly and increase the chance that you'll get publicly and anonymously hand-slapped.

On HN and StackOverflow:

1. These are not places that non-techs would tend to frequent, and they mostly evolved into more serious areas, unlike Slashdot, which gave points for "funny", etc.

2. People are typically serious enough to self-regulate or community-regulate via negative voting.

So, I'd not provide points for funny, and I'd cut off editing and negative voting early after the post (like HN), as continuous negative voting is demoralizing.

One more thing: general forums are more likely to get vandalized.