If a website could be sure none of their users are malicious/bots and all of the users are perfectly rational and virtuous then public or private voting wouldn’t matter either way. That being nearly impossible, why not a reputation based system like Stack Exchange? Only when an account meets certain requirements they can vote.

To boot, on the website tweakers.net one can actually vote -1, …, +3.

• +3: “Spotlight comments are of such high quality and substantive value that they clearly stand out above the rest”
• +2: “Informative and interesting comments that are a useful addition to the discussion in an on-topic thread or the information in the article”
• +1: “Nice on-topic responses with knowledge that is common knowledge”
• +0: “Comments that do not contain a relevant contribution, but are posted with good intentions”
• -1: “Flamebaits, trolls, misplaced jokes, unnecessarily hurtful comments and other comments that violate our terms and conditions or house rules”

[Posted this comment on GitHub.]