Slashdot's system was best. No upvoting, certainly no downvoting, just a small vocabulary of tags: "informative", "insightful", "irrelevant", etc. And of course

Slashdot's system was best. No upvoting, certainly no downvoting, just a small vocabulary of tags: "informative", "insightful", "irrelevant", etc. And of course "funny". That way you can literally turn the humor off!