A refresher course on how this works:
Each poster starts with 10 points. Positive comments add points. When you reach 100 points, you get a second pitchfork, and gain another with every hundred points given by others. After reaching 500 points, it takes another 200 points to gain a pitchfork -- these are indicated with a shadow (line) underneath it. A person with multiple pitchfork shadows have amassed an amazing number of positive comments. Kudos to them!
Negative comments take away points. When a poster's value equals 0, a gray rectangle is shown (meaning neutral). At -1, a flame is shown. If the total point value is -100 or more, there are two flames, -200 is three flames, etc. It takes an extraordinary effort to get to two flames.
How many points are given? It's an algorithm that takes into account longevity, pitchforks (or flames), participation in the commenting system, and a few other variables. It is an algorithm buried in the contents of the board software and not something that's available to either parse out or change. The first few comments a poster leaves are worth 0 points. Once the poster has participated some, they have earned the privilege (according to the software developers) to start amending other people's point count. If they are a member in good standing, they might add 1 point, working up to somewhere around 10 or more points. A negative comment counts only for a fraction, perhaps knocking off fewer than half (maybe even a third) of the points. Again, the algorithm is not exposed, so I apologize for not giving concrete rules. What you can take away is that good comments rack up faster than bad. If a poster has flames, they cannot alter another poster's pitchfork value.
You also have to "spread it around." This helps to prevent artificial inflation amongst cliques. If you comment on a post, you can't give another comment to that poster until you give quite a substantial (but attainable) number of comments by other posters. This does penalize a poster who puts out a lot of very good content. It also spares a poster who posts a lot of poor posts (use the whistle at the bottom of each post to report poor content that you think violates the rules). On the whole, though, it allows the community to give feedback to exceptional posters.
As you can see, it takes more than a comment or two to change the number of pitchforks (or flames). Typically you'd have to have more than one negative comment (usually 2-3) to see a flame, and perhaps 20 or more to get to a second flame. Likewise, it takes 10-20 or more comments to garner another pitchfork. It all depends on who is giving the comments. On the whole, it's a pretty fair system. However, the unsigned negative comments seem to be a sticking point. On the one hand, it give the ability to give constructive criticism, "Your post is one that doesn't fit our community, so shape up," without fear of retribution. On the other hand, it allows someone to privately blast another poster. This is not what it should be used for. If it's not civil, please PM any of the mods and we can take care of that. Board rules apply to comments and we can and will give infractions for comments.
If you receive an anonymous negative comment that does not run afoul of the board rules but does rub you the wrong way, I've got some advice. First, ask yourself: is there any shred of truth to the comment? Is there something I could have done better? If so, consider that the next time you post. If not, assume the coward is is mouthing off because he/she can and move on. Pretend it was something overheard while in a crowd. Let it bother you for a minute, reflect on it a moment to determine if you did cross a line somewhere, then let it go.
And if you don't like anonymous comments, please don't leave them.
Are you reading along wondering whether you've received comments? Go to the Settings link at the very top of the page. You'll see the last 10 comments you've received. A pitchfork gave you points for a positive comment, a flame represents a negative comment that deducted points, and a gray box indicates that it did not alter your point total and you'll need to read it for context.
I hope this helps. Nobody should get too bent out of shape about anonymous constructive criticism -- or even anonymous blathering. First consider if the comment has a point (regardless of how poorly it's articulated), then consider the source. Stupidity by an anonymous source isn't worth getting upset about. If it violates the rules, report it to the moderators. How? Highlight the comment, then cut the text into the copy buffer - ctrl-c on Windows machines. Click on the link to your post (just above the comment), then click on the whistle below your post to report it. Tell us that you received a comment and paste the comment into your explanation -- ctrl-v on Windows machines. This will let all moderators know what you received and an administrator will look into it promptly.