This is a really great site. Thank you!

I would love to see a rating system as well. However, there are two problems that I see with using a plus/minus system.

First, I think that users will likely feel that they have to give a rating to the posts they view and if they do not think that the post is bad they will give it a "plus" even if they don't think that the post is really that good. They won't want to penalize a comment that they find to be just OK.

Secondly, only having two options does note allow the user to express their opinion of the post very accurately. By having multiple options the user will be able to express their opinion more accurately according to their own tastes in what makes a comments good.

What I propose is that there should be four buttons: [Poor], [OK}, [Good], and [Great].
Where [Poor] subtracts one point, [OK] does nothing, [Good] adds one point, and [Great] adds two points. This will allow the user to indicate posts that they think are really great, better then average, average (or there is nothing wrong with it), and below average. Since by their very nature the posts on this site are supposed to be the best already the average of all of the posts should be zero. This is because in order to give the most accurate indication of quality of ALL of the posts, the individual posts rating needs to be relative to all of the other post. My system will better enable this than a "1-10" system. My system will also work better than a simple plus/minus system because it will allow the user to more accurately express their opinion of the post.

Ideally, the ratings of all posts should be periodically adjusted so that their average rating is zero. Furthermore, the type of rating that each user gives should be tracked so that people who constantly rate posts as "poor" or as "great" too frequently can be corrected. This should be done because people who rate too often in extremes are not as likely to be thinking about how the post should be rated relative to other posts (remember that the posts here are already supposed to be really good). This could be corrected for by changing the users extreme rating to the less extreme rating i.e. a "poor" rating would become an "OK" rating.

A "star" based system (or similar) could be used to display the ratings to the users. The displayed rating of each post would be determined by what percentile the post falls in. So a one star rating could be the bottom 5%, a five star rating could be the middle 5% and ten stars could be the top 5%. The worst rated posts that have enough ratings could be removed.

Alternatively, a bar graph could be used to indicate a posts rating. The bar graph should be adjusted so that the post with the lowest rating would receive a zero and the post with the highest rating would receive the highest number. This would also provide a number that shows a particular posts position among the other posts.

This system will allow for the truly great posts to stand out and for the lesser posts to be weeded out. Of course since the posts here are already really good it is unlikely that there will be very many posts that will get a "poor" rating.

For additional interest highly contested posts could be marked as such.