There must be a better way to asses the "value" of content. I agree that the down vote is arguably a good gauge for how the community at large "feels" about the content but not a good indicator for "value". There are two metrics here that I do not believe can be extracted from a voting system.

I rarely comment, one of the few time I did I got down voted. I returned 3 days later and tried to defend my position, but it was too late and the community had move on. Oddly enough my comment did start a thread of discussion.

As I mentioned in my followup comment assessing the value of user contributed content is an area that we are trying to solve in a web application solution soon to be deployed.

Below is an excerpt from my comment.

"Using my initial comment as an example had I not posted that comment "value adding" content would never have been created. If my contributed content resulted in "value adding" content, is it not then "value adding" content? Is a good proxy of "value adding" content, content which produces or causes other content creation?"

So if a comment gets down voted but starts a wave of discussion surely it has value.