Steve, the rationale for marking a post as edited is to let the reader know it might have changed. This holds regardless of whether a reply has been posted or not. Without the edit indicator you either have to assume something you believe you've read hasn't changed or read it again to find out if it has or hasn't.
What is the downside of marking something as edited, in your view? I don't see how the edit indicator gets in the way or is confusing - it's smaller and in lighter colour to let the user know it's not part of the original text.
You mention that if the earlier post had still been editable you wouldn't need to have added another, but what is the problem with adding another? I'd argue that adding a new post is more friendly for other users, otherwise they may well miss the addition. It also works better for users who are using either the "read new posts" option, or has "email new posts" turned on.
...and had the above post not been locked I would not need to make this new one this morning to add:
The point of any software interface is be transparent and not get in the way. All the more important for a forum aimed at pilot's for whom English is a second language.
True but please explain the reasoning for marking a post that has not been replied to as edited in the first place?
I'm just trying to help you make the forum interface logical and as user friendly as possible.
There! this post is marked as edited yet no one posted after it so what purpose did marking it edited serve. People could now think I edited after a reply changing it's meaning which is not the case. Marking as edited only after a reply makes sense. Otherwise it is ambiguous.
Not sure I follow this. The "Last Edited" indication includes the date and time, so anybody who cared enough can see whether it was edited before or after any replies were added.
Steve
I take on board your point, but we are trying to think ahead and avoid situations which do occur elsewhere and which do cause problems.
We have tried to avoid speaking negatively of other sites (not least because a lot of people here are non-UK and probably wouldn't know them) but I've been hanging around these communities - UK and US - for a decade and have seen all kinds of stuff. David too; his company hosts some far bigger online communities.
I would argue that a lot of trouble is facilitated by mods tolerating stuff they should not tolerate, but mods can't be everywhere 24/7 - well not unless you have the whole of the Swanwick ATC centre working for you during their breaks 
A typical example might be someone posting a troll and when this has kicked off a comment elsewhere, they edit or delete their post.
Often it leads to a big scene which causes a number of good people to depart for good, and an awful lot of work for the moderators who have to confer between themselves as to how far to let it go before it might degenerate into something with a "legal" potential. We don't have the manpower for that...
Currently we have a nice bunch of people here. This is partly because the initial promotion involved me extracting several thousand email addresses from my personal email archive (going back ~12 years) and then manually stripping out all known pilot forum troublemakers before emailing the list There weren't many; perhaps 10-20. I know I missed a few, but anyway anyone can join up. If they join up and contribute sensibly, they will be welcome.
Now there is a 2-hour editing slot which should be plenty for correcting any mistakes in one's post.
If someone has written something which they feel is really a problem (for e.g. legal reasons) we (the mods) can edit posts at any later time.
I can't see any issue with allowing a post to be edited or deleted indefinitely if no one has replied. Editing even after someone has replied does not seem to have been abused, at least on the pilot forums I have used. All of those allow it. I am quite capable of typing something I checked for typos yet will look back at it the next day and it's a syntax nightmare. Perhaps it is an age thing :(
edited to test feature and...
There! this post is marked as edited yet no one posted after it so what purpose did marking it edited serve. People could now think I edited after a reply changing it's meaning which is not the case. Marking as edited only after a reply makes sense. Otherwise it is ambiguous.
Okay, thanks.
BP, I've increased it the edit time to 2 hours. Let's see how things go.
The trouble with allowing edits after longer if nobody has replied is that people may read the thread, including the pre-edit post, then come back to the thread later and read subsequent posts, without realising that an earlier post has now been changed.
Out of curiosity I looked at the T&C of "that other site"
There's no problem at all mentioning other sites, by name. Indeed, it's better if you do, not least because I am not sure to which one you're referring here! PPRuNe? Flyer?
Most of the better T&Cs do state a term and of the 5 that I've just looked at 3 said perpetual and 2 didn't say either way. Certainly that's what we'll do here, for the reasons of practicality stated earlier.
We could increase it to a couple of hours because certainly the posts on here tend to be long and are sometimes quite technical and involved. Would that help?
Sometimes I post late at night, and only notice my spelling errors the morning after. Would 12 hours be a nice compromise?
Furthermore, the UK forum greatly relaxes its rules with regards to editing as long as no reply has been entered in the system. Sounds like a good idea in principle, but I have no idea how hard that is to implement.
However, in common with lots of sites, the licence you grant us to publish your materials is perpetual and not something you can revoke.
Out of curiosity I looked at the T&C of "that other site" and they are actually not clear on whether the license is perpetual and non-revokable. The only thing they say is this:
By displaying or posting content on the Site, you hereby grant us a nonexclusive global license to publish the content submitted by you to the Site.
The "UK Forum" has no specific copyright legalese as far as I can see.
But I fully agree that it's going to be extremely hard to remove content from the site, and all its caches. So working on the assumption that the license is perpetual makes a lot of sense.
The trouble is BackPacker people really do alter posts in a way that undermines the discussion. At the moment the discussion on these forums is fabulous - friendly, informative, well-researched and so on, but it's unrealistic to think that there won't end up being some robust arguments and that's when this becomes an issue. The 30 minute time limit is meant for a "I pressed go when I didn't mean to" or "I typed that URL in wrong and I want to fix it" scenario. We could increase it to a couple of hours because certainly the posts on here tend to be long and are sometimes quite technical and involved. Would that help? I wouldn't be happy to do away with the time limit entirely.
As for the legal position, you're right we've not yet got around to posting something and we probably should. It's true that you will retain the copyright for your posts. However, in common with lots of sites, the licence you grant us to publish your materials is perpetual and not something you can revoke. To be honest, anything else just isn't practical - the Internet being what it is it would be effectively impossible for us to un-publish something completely, even if it was deleted from our site it would still exist in other forms such as search engine databases and such like.
