It's not necessary to post a reason in the forum, or to send an email. If you have logged in, and are looking at a comments page, then there will be a "My Posts" link on the right-hand side of the top of the page. You can see there whether your posts have been accepted or rejected. For rejected posts, it would be possible, time permitting, to have the post tagged with a reason for rejection.
It also allows you to review all of your previous posts, warts, typo's and all! Wish I could edit out some of the howlers I have made.