Here's how to make downvoting work: emulate Stack Exchange

The Stack Exchange QA sites have the concept of "reputation", which is a score you get by having good questions or answers voted up by others. They also have downvoting, which reduces the recipient's reputation — but the key thing that makes it work is that downvotes also cost the downvoter. You can (and people do) vote down bad information, but there's a cost.

If you don't have enough reputation — a simple representation of credibility built up through good posts — you can't downvote at all. In fact, you have to have a minimal reputation to even vote up (which prevents abuse of the system).

If we're going to have downvoting here, we should emulate that.

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Matthew Miller « http://mattdm.org/ »