If the goal is that people should not be punished, how about the rule "do not downvote into negative score". That way it can never cost karma to post here, but people can still adjust the score of a recommendation downwards. If only positive votes are allowed, the scores will over-value controversial recommendations.
I think this almost cancels out.
If a high-scoring, highly controversial recommendation gets in such a situation, it means it got enough attention to be controversial and reached quite a few people, and is giving us some nice data on who likes what and how the LW population stands on this, assuming there's some kind of written feedback. I think that data is probably worth the karmic difference.
This is the monthly thread for posting media of various types that you've found that you enjoy. I find that exposure to LW ideas makes me less likely to enjoy some entertainment media that is otherwise quite popular, and finding media recommended by LWers is a good way to mitigate this. Post what you're reading, listening to, watching, and your opinion of it. Post recommendations to blogs. Post whatever media you feel like discussing! To see previous recommendations, check out the older threads.
Rules: