Ah... my opportunity came quickly once I knew to look for it.
I just made the 1st response in the What's the point of advanced governments?
thread. In this case it's directly in the GalCiv II forum as opposed to a subforum of the GalCiv II forum.
Immediately after posting the response I checked for the edit button on the 1st reply and it was not present although it was and at this moment still is present after the 2nd reply although so far it's only been 2 minutes since I posted that reply.
I think I'll wait to see how long it takes for the edit button to go away. Of course the times are approximate since forum time and the time on my PC don't precisely match.
4 minutes and the edit button is still there.
5 minutes and the edit button is still there.
7 minutes and the edit button is still there in fact I actually edited the post wondering if this extends the window of editablilty.
8 minutes and the edit button is still there.
9 minutes and the edit button is still there.
11 minutes and the edit button is still there and I edited it again just for yuks.
13 minutes and the edit button is still there but I tire of this game. I'll check back a little later but I won't wait to post this reply.
16 minutes and the edit button is still present. Also the time of this reply allowed me to correlate my PC time to forum time and all the times listed above are actually 2 minutes behind so it's actually been 18 minutes since my reply that it has remained editable. Of course anyone else replying would kill the ability as well.
23 minutes (by corrected count) and the reply is still editable.
Hmm... beyond the half hour point now and still editable.
So in conclusion the OP is *always* editable, Reply #1 is *never* editable and any later replies are editable until someone posts a later reply with no obvious time limit (up to 40 minutes at the moment).
It's close to 6 hours after I posted this reply and I can still edit it so I doubt that there is any time limit on editing a reply other than someone else replying to the thread after you.
Also editable is not a real word but I'm sure you get the drift. I suppose to be technically proper it should be edit-able but that looks too funny.