Coming from a game development background ("real" games not "social" games), there are feedback issues with the voting system. Frankly, I don't vote a lot because I don't understand the system. I usually only up-vote one story a day.
Sometimes, if there is a "crap" story in the top 5 I will up-vote the other 4.
Look up the term "meaningful choice" in the book Rules of Play.
The problem is that I don't have to choose between story A and B. I can up vote them both because there is no scarcity built into the system.
I don't even think there is a scarcity model with voting. How many up votes do I get in a day? If there is a model then I don't understand it. That implies the second issue with the system is that there is a lack of feedback.
This isn't only an HN problem. I see the same problems with other social sites that try to implement voting or other game mechanics.
Focus on improving the system for good players. Don't focus on squashing behaviour by bad players trying to game the system. The good players will police the bad players if the system is fairly balanced. No one reads the instruction manual, therefore the good behaviour has to be designed into the system. And feedback, feedback, feedback. There needs to be better feedback when there is good behaviour.
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