Way back in October 2009 Reddit introduced their "Best" comment sorting system. We've just pulled those changes into Less Wrong. The changes affect only comments, not stories.
It's good. It should significantly improve the visibility of good comments posted later in the life of an article. You (yes you) should adopt it. It's the default for new users.
See http://blog.reddit.com/2009/10/reddits-new-comment-sorting-system.html for the details.
If you use the Bayes approach with a Beta(x,y) prior, all you do is for each post add x to the # of upvotes, add y to the # of downvotes, and then compute the % of votes which are upvotes. [1]
In my college AI class we used this exact method with x=y=1 to adjust for low sample size. Someone should switch out the clunky frequentist method reddit apparently uses with this Bayesian method!
[1] This seems to be what it says in the pdf.