It's interesting to think about what the perfect balance is, when sites like reddit, quora, and stack overflow all use "social influence" as a means of motivation. But that same driving force slowly drives the quality of the content into the ground. How do you strike a balance?
I think HN's approach of hiding vote counts is definitely a step in the right direction to cultivate quality.
Edit: Link to PDF for those too lazy to figure out where to click. (http://www.pnas.org/content/early/2011/05/10/1008636108.full...)