I was a moderator for many years in another forum that happened to be the world's largest (over 260,000 members) for a different hobby group, and my experiences there taught me a lot about how forums work. Allowing a limited window for editing is the best approach by far (it was also that other forum's policy), but unlimited (open) editing is a recipe for disaster. I have seen how easy it is in an open editing environment for someone to turn a long and interesting thread (topic) into utter nonsense because that person decided to change what they had previously written and thereby rendering replies to those post meaningless. I have also seen what damage can be done to a forum when someone maliciously decides to go back and edit their posts, or just outright delete all of the content from them. And from a moderation standpoint, open editing is a nightmare as it becomes impossible to manage a forum when old content remains fluid. Such a situation, for example, allows would-be spammers to sneak objectionable content into a post after it has been read by a moderator by simply editing the content of a very old post.
It would surprise me that any forum would allow open editing, because those that do must not be very concerned with its rules, combating spam, or the malicious actions of disgruntled members.
I fully understand the need to be able to fix a mistake that you had just made in a recent post, or perhaps add something to it that only occurred to you after you had clicked on the post button, and that's what I would like everyone here to be able to do. However, at some point whatever you've written has to remain in the record if any integrity is to be maintained. Retroactively changing the nature of previously posted content, perhaps as a result of the comments of those replying to it, is not how life works, nor a reflection of reality, and I don't think such an approach is fundamentally good for a public forum.
