Hmmm...I disagree a bit with number one.

While I feel that some nitpicky comments over simple typos are unnecessary and mean, there is often times when pointing out grammatical errors in what is supposed to be a business letter can be helpful.

I see nothing wrong with comments such as "Turn off the caps lock" or "You should try using paragraphs." Also, if a letter is so poorly writen that the letter-writer's point does not get across, I see no harm in pointing this out and making some suggestions as to how it can be fixed.

Since PlanetFeedback feels so strongly about commenters no longer touching on the subject of grammar, perhaps someone on the PFB team could be assigned to reviewing all letters and assisting letter-writers with grammar, sentence structure, and the like.