I am assuming that if a moderator edits a post, there is no indication that it has been edited, unlike when a user edits their own posts?
If this is the case, I'd like to propose an option where a moderator could include a reason for editing a post and when they do this the name of the moderator, the date and the reason are then all displayed at the bottom of the post in smaller text. If no reason is included then no indication of editing would be displayed.
This is something that can be done in phpBB. I found it useful at times to let a user know why their post had been edited, whereas at other times there was no need to (such as correcting a post where BBcode tags hadn't been correctly used or a editing a URL because it was broken).
Of course this can be done manually now by typing into the bottom of a post why it was edited, who edited it and when, then styling the text to a smaller size. I just thought it would be nice to have an option for this built-in that did most of this automatically.