I've read about people wanting an edit post button. Then an add-on button to the post. However, a way to fix these mistakes before they are even posted in the first place is a "Preview Post" button.
You write your post, and instead of just the option to post what you've written, you can also preview it, before it goes up on the board for all to see. It's already been implemented in a number of other forums, from the metal-archives forum, to the explosm forum, and many many more.
This would mostly be useful for seeing if your codes have worked (urls, images, quotes), and would prevent double and triple postings whilst people try to get it right.
