This is one of those situations where every approach has serious upsides and potential downsides, and it comes down to the general “vibe” a particular community wants to have.
With that in mind, we’d like to make it so that it’s publicly visible if a post’s been edited, and the time it was most recently edited. But we’d like to hide the actual edits, so only moderators can see earlier versions of the post.
The five-minute grace period for ninja edits takes care of most problems. And people who want to make a Permanent Record Of Your Comment will do so anyway with screengrabs, or simply by quoting you in their replies. But that seems enough – we don’t need to encourage mistake-mining by making them permanently accessible.
Sometimes it is best to let hot-heads revise their thoughts later, without it drawing attention to the specifcs of whatever they said. It’s good to know they’ve edited it, but faciliting access to misjudged remarks or badly-composed posts will just fuel embarassment and hostility.
In return for giving our hamfisted, meatbrained commentariat a hidden edit history, perhaps we can punish them with a more prominent indication that “This post was last edited at XX:XX”, say, as copy text under the post.
If hidden histories turn out to be a problem, encouraging trolls or whatnot, we can always just expose them again!
